Carbon dioxide sequestration involving two-salt-based thermolytic processes

ABSTRACT

The present invention relates to an energy efficient carbon dioxide sequestration processes whereby Group 2 silicate minerals and CO 2  are converted into limestone and sand using a two-salt thermolytic process that allows for the cycling of heat and chemicals from one step to another.

The present application claims priority to U.S. Provisional ApplicationSer. Nos. 61/362,607, filed Jul. 8, 2010, 61/370,030, filed Aug. 2,2010, 61/406,536, filed Oct. 25, 2010, and 61/451,078, filed Mar. 9,2011, the entire contents of each of which are incorporated herein byreference in their entirety.

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention generally relates to the field of removing carbondioxide from a source, such as the waste stream (e.g. flue gas) of apower plant, whereby Group 2 silicate minerals are converted into Group2 chloride salts and SiO₂, Group 2 chloride salts are converted intoGroup 2 hydroxide and/or Group 2 hydroxychloride salts. These in turnmay be reacted with carbon dioxide to form Group 2 carbonate salts,optionally in the presence of catalysts. These steps may be combined toform a cycle in which carbon dioxide is sequestered in the form ofcarbonate salts and byproducts from one or more steps, such as heat andchemicals, are re-used or recycled in one or more other steps.

II. Description of Related Art

Considerable domestic and international concern has been increasinglyfocused on the emission of CO₂ into the air. In particular, attentionhas been focused on the effect of this gas on the retention of solarheat in the atmosphere, producing the “greenhouse effect.” Despite somedebate regarding the magnitude of the effect, all would agree there is abenefit to removing CO₂ (and other chemicals) from point-emissionsources, especially if the cost for doing so were sufficiently small.

Greenhouse gases are predominately made up of carbon dioxide and areproduced by municipal power plants and large-scale industry insite-power-plants, though they are also produced in any normal carboncombustion (such as automobiles, rain-forest clearing, simple burning,etc.). Though their most concentrated point-emissions occur atpower-plants across the planet, making reduction or removal from thosefixed sites an attractive point to effect a removal-technology. Becauseenergy production is a primary cause of greenhouse gas emissions,methods such as reducing carbon intensity, improving efficiency, andsequestering carbon from power-plant flue-gas by various means has beenresearched and studied intensively over the last thirty years.

Attempts at sequestration of carbon (in the initial form of gaseous CO₂)have produced many varied techniques, which can be generally classifiedas geologic, terrestrial, or ocean systems. An overview of suchtechniques is provided in the Proceedings of First National Conferenceon Carbon Sequestration, (2001). To date, many if not all of thesetechniques are too energy intensive and therefore not economicallyfeasible, in many cases consuming more energy than the energy obtainedby generating the carbon dioxide. Alternative processes that overcomeone or more of these disadvantages would be advantageous.

The referenced shortcomings are not intended to be exhaustive, butrather are among many that tend to impair the effectiveness ofpreviously known techniques for removing carbon dioxide from wastestreams; however, those mentioned here are sufficient to demonstratethat the methodologies appearing in the art have not been altogethersatisfactory and that a significant need exists for the techniquesdescribed and claimed in this disclosure.

SUMMARY OF THE INVENTION

Disclosed herein are methods and apparatuses for carbon dioxidesequestration, including removing carbon dioxide from waste streams. Inone aspect there are provided methods of sequestering carbon dioxideproduced by a source, comprising:

-   (a) reacting a first cation-based halide, sulfate or nitrate salt or    hydrate thereof with water in a first admixture under conditions    suitable to form a first product mixture comprising a first step (a)    product comprising a first cation-based hydroxide salt, a first    cation-based oxide salt and/or a first cation-based hydroxychloride    salt and a second step (a) product comprising HCl, H₂SO₄ or HNO₃;-   (b) admixing some or all of the first step (a) product with a second    cation-based halide, sulfate or nitrate salt or hydrate thereof and    carbon dioxide produced by the source in a second admixture under    conditions suitable to form a second product mixture comprising a    first step (b) product comprising a first cation-based halide,    sulfate and/or nitrate salt or hydrate thereof, a second step (b)    product comprising a second cation-based carbonate salt, and a third    step (b) product comprising water; and-   (c) separating some or all of the second cation-based carbonate salt    from the second product mixture,    whereby the carbon dioxide is sequestered into a mineral product    form.

In some embodiments, the first cation-based halide sulfate or nitratesalt or hydrate thereof of step (a) is a first cation-based chloridesalt or hydrate thereof, and the second step (a) product is HCl. In someembodiments, the first cation-based halide, sulfate, or nitrate salt orhydrate thereof of step (b) is a first cation-based chloride salt orhydrate thereof.

In some embodiments, the first cation-based chloride salt or hydratethereof of step (a) is MgCl₂. In some embodiments, the firstcation-based chloride salt or hydrate thereof of step (a) is a hydratedform of MgCl₂. In some embodiments, the first cation-based chloride saltor hydrate thereof of step (a) is MgCl₂.6H₂O. In some embodiments, thefirst cation-based hydroxide salt of step (a) is Mg(OH)₂. In someembodiments, the first cation-based hydroxychloride salt of step (a) isMg(OH)Cl. In some embodiments, the first step (a) product comprisespredominantly Mg(OH)Cl. In some embodiments, the first step (a) productcomprises greater than 90% by weight Mg(OH)Cl. In some embodiments, thefirst step (a) product is Mg(OH)Cl. In some embodiments, the firstcation-based oxide salt of step (a) is MgO.

In some embodiments, the second cation-based halide, sulfate or nitratesalt or hydrate thereof of step (b) is a second cation-based chloridesalt or hydrate thereof, for example, CaCl₂. In some embodiments, thefirst cation-based chloride salt of step (b) is MgCl₂. In someembodiments, the first cation-based chloride salt of step (b) is ahydrated form of MgCl₂. In some embodiments, the first cation-basedchloride salt of step (b) is MgCl₂.6H₂O.

In some embodiments, some or all of the water in step (a) is present inthe form of steam or supercritical water. In some embodiments, some orall of the water of step (a) is obtained from the water of step (b). Insome embodiments, step (b) further comprises admixing sodium hydroxidesalt in the second admixture.

-   -   In some embodiments, the methods further comprise:    -   (d) admixing a Group 2 silicate mineral with HCl under        conditions suitable to form a third product mixture comprising a        Group 2 chloride salt, water, and silicon dioxide.

In some embodiments, some or all of the HCl in step (d) is obtained fromstep (a). In some embodiments, the methods of step (d) further comprisesagitating the Group 2 silicate mineral with HCl. In some embodiments,some or all of the heat generated in step (d) is recovered. In someembodiments, some or all of the second cation-based chloride salt ofstep (b) is the Group 2 chloride salt of step (d). In some embodiments,the methods further comprise a separation step, wherein the silicondioxide is removed from the Group 2 chloride salt formed in step (d). Insome embodiments, some or all of the water of step (a) is obtained fromthe water of step (d).

In some embodiments, the Group 2 silicate mineral of step (d) comprisesa Group 2 inosilicate. In some embodiments, the Group 2 silicate mineralof step (d) comprises CaSiO₃. In some embodiments, the Group 2 silicatemineral of step (d) comprises MgSiO₃. In some embodiments, the Group 2silicate mineral of step (d) comprises olivine (Mg₂[SiO₄]). In someembodiments, the Group 2 silicate mineral of step (d) comprisesserpentine (Mg₆[OH]₈[Si₄O₁₀]). In some embodiments, the Group 2 silicatemineral of step (d) comprises sepiolite (Mg₄[(OH)₂Si₆O₁₅].6H₂O),enstatite (Mg₂[Si₂O₆]), diopside (CaMg[Si₂O₆]), and/or tremoliteCa₂Mg₅{[OH]Si₄O₁₁}₂. In some embodiments, the Group 2 silicate furthercomprises iron and or manganese silicates. In some embodiments, the ironsilicate is fayalite (Fe₂[SiO₄]).

In some embodiments, some or all of the first cation-based chloride saltformed in step (b) is the first cation-based chloride salt used in step(a).

In some embodiments, the carbon dioxide is in the form of flue gas,wherein the flue gas further comprises N₂ and H₂O.

In some embodiments, suitable reacting conditions of step (a) comprise atemperature from about 200° C. to about 500° C. In some embodiments, thetemperature is from about 230° C. to about 260° C. In some embodiments,the temperature is about 250° C. In some embodiments, the temperature isfrom about 200° C. to about 250° C. In some embodiments, the temperatureis about 240° C.

In some embodiments, suitable reacting conditions of step (a) comprise atemperature from about 50° C. to about 200° C. In some embodiments, thetemperature is from about 90° C. to about 260° C. In some embodiments,the temperature is from about 90° C. to about 230° C. In someembodiments, the temperature is about 130° C.

In some embodiments, suitable reacting conditions of step (a) comprise atemperature from about 400° C. to about 550° C. In some embodiments, thetemperature is from about 450° C. to about 500° C.

In some embodiments, suitable reacting conditions of step (a) comprise atemperature from about 20° C. to about 100° C. In some embodiments, thetemperature is from about 25° C. to about 95° C.

In some embodiments, suitable reacting conditions of step (a) comprise atemperature from about 50° C. to about 200° C. In some embodiments, thetemperature is from about 90° C. to about 150° C.

In another aspect, the present invention provides methods ofsequestering carbon dioxide produced by a source, comprising:

-   -   (a) admixing a magnesium chloride salt and water in a first        admixture under conditions suitable to form (i) magnesium        hydroxide, magnesium oxide and/or Mg(OH)Cl and (ii) hydrogen        chloride;    -   (b) admixing (i) magnesium hydroxide, magnesium oxide and/or        Mg(OH)Cl, (ii) CaCl₂ and (iii) carbon dioxide produced by the        source in a second admixture under conditions suitable to        form (iv) calcium carbonate, (v) a magnesium chloride salt,        and (vi) water; and    -   (c) separating the calcium carbonate from the second admixture,        whereby the carbon dioxide is sequestered into a mineral product        form.

In some embodiments, some or all of the hydrogen chloride of step (a) isadmixed with water to form hydrochloric acid. In some embodiments, someor all of the magnesium hydroxide, magnesium oxide and/or Mg(OH)Cl ofstep (b)(i) is obtained from step (a)(i). In some embodiments, some ofall the water in step (a) is present in the form of a hydrate of themagnesium chloride salt. In some embodiments, step (a) occurs in one,two or three reactors. In some embodiments, step (a) occurs in onereactor. In some embodiments, the magnesium hydroxide, magnesium oxideand/or Mg(OH)Cl of step (a)(i) is greater than 90% by weight Mg(OH)Cl.In some embodiments, the magnesium chloride salt is greater than 90% byweight MgCl₂.6(H₂O).

In some embodiments, the methods further comprise:

-   -   (d) admixing a Group 2 silicate mineral with hydrogen chloride        under conditions suitable to form a Group 2 chloride salt,        water, and silicon dioxide.

In some embodiments, some or all of the hydrogen chloride in step (d) isobtained from step (a). In some embodiments, step (d) further comprisesagitating the Group 2 silicate mineral with the hydrochloric acid. Insome embodiments, some or all of the magnesium chloride salt in step (a)is obtained from step (d). In some embodiments, the methods furthercomprise a separation step, wherein the silicon dioxide is removed fromthe Group 2 chloride salt formed in step (d). In some embodiments, someor all of the water of step (a) is obtained from the water of step (d).In some embodiments, the Group 2 silicate mineral of step (d) comprisesa Group 2 inosilicate.

In some embodiments, the Group 2 silicate mineral of step (d) comprisesCaSiO₃. In some embodiments, the Group 2 silicate mineral of step (d)comprises MgSiO₃. In some embodiments, the Group 2 silicate mineral ofstep (d) comprises olivine. In some embodiments, the Group 2 silicatemineral of step (d) comprises serpentine. In some embodiments, the Group2 silicate mineral of step (d) comprises sepiolite, enstatite, diopside,and/or tremolite. In some embodiments, the Group 2 silicate furthercomprises mineralized iron and or manganese.

In some embodiments, step (b) further comprises admixing CaCl₂ and waterto the second admixture.

Other objects, features and advantages of the present disclosure willbecome apparent from the following detailed description. It should beunderstood, however, that the detailed description and the specificexamples, while indicating specific embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and areincluded to further demonstrate certain aspects of the presentdisclosure. The invention may be better understood by reference to oneof these drawings in combination with the detailed description ofspecific embodiments presented herein.

FIG. 1 is block diagram of a system for a Group 2 hydroxide-basedprocess to sequester CO₂ as Group 2 carbonates according to someembodiments of the present invention.

FIG. 2 is block diagram of a system in which Mg²⁺ functions as acatalyst for the sequestration of CO₂ as calcium carbonate according tosome embodiments of the present invention.

FIG. 3 is a simplified process flow diagram according to someembodiments of the processes provided herein. Shown is a Group-IIhydroxide-based process, which sequesters CO₂ as limestone (composedlargely of the mineral calcite, CaCO₃). The term “road salt” in thisfigure refers to a Group II chloride, such as CaCl₂ and/or MgCl₂, eitheror both of which are optionally hydrated. In embodiments comprisingMgCl₂, heat may be used to drive the reaction between road salt andwater (including water of hydration) to form HCl and magnesiumhydroxide, Mg(OH)₂, and/or magnesium hydroxychloride, Mg(OH)Cl. Inembodiments comprising CaCl₂, heat may be used to drive the reactionbetween road salt and water to form calcium hydroxide and HCl. The HClis reacted with, for example, calcium inosilicate rocks (optionallyground), to form additional road salt, e.g., CaCl₂, and sand (SiO₂).

FIG. 4 is a simplified process-flow diagram corresponding to someembodiments of the present invention. Silicate rocks may be used in someembodiments of the present invention to sequester CO₂ as CaCO₃. The term“road salt” in this figure refers to a Group II chloride, such as CaCl₂and/or MgCl₂, either or both of which are optionally hydrated. In theroad salt boiler, heat may be used to drive the reaction between roadsalt, e.g., MgCl₂.6H₂O, and water (including water of hydration) to formHCl and Group II hydroxides, oxides, and/or mixed hydroxide-chlorides,including, for example, magnesium hydroxide, Mg(OH)₂, and/or magnesiumhydroxychloride, Mg(OH)Cl. In embodiments comprising CaCl₂, heat may beused to drive the reaction between road salt and water to form calciumhydroxide and HCl. The HCl may be sold or reacted with silicate rocks,e.g., inosilicates, to form additional road salt, e.g., CaCl₂, and sand(SiO₂). Ion exchange reaction between Mg²⁺ and Ca²⁺ may used, in some ofthese embodiments, to allow, for example, the cycling of Mg²⁺ ions.

FIG. 5 is a process flow diagram showing parameters and results from aprocess simulation using Aspen Plus process software. In thisembodiment, a 35% MgCl₂, 65% H₂O solution is heated to 536° F. (280°C.), then the stream leaves in the stream labeled “H₂O—MgOH,” whichcomprises a solution of MgCl₂ and solid Mg(OH)₂. Typically, whenMg(OH)Cl dissolves in water it forms Mg(OH)₂ (solid) and MgCl₂(dissolved). Here the MgCl₂ is not used to absorb CO₂ directly, ratherit is recycled. The net reaction is the capture of CO₂ from flue gasusing inexpensive raw materials, CaCl₂ and water, to form CaCO₃. Resultsfrom the simulation suggest that it is efficient to recirculate a MgCl₂stream and then to react it with H₂O and heat to form Mg(OH)₂. One ormore of the aforementioned compounds then reacts with a CaCl₂/H₂Osolution and CO₂ from the flue gas to ultimately form CaCO₃, which isfiltered out of the stream. The resulting MgCl₂ formed is recycled tothe first reactor to repeat the process.

FIG. 6 is a process flow diagram showing parameters and results from aprocess simulation using Aspen Plus process software. The net reactionis the capture of CO₂ from flue gas using inexpensive raw materials,CaCl₂ and water, to form CaCO₃. In this embodiment, the hexahydrate isdehydrated in three separate chambers and decomposed in the fourthchamber where the HCl that is formed from the decomposition isrecirculated back to the third chamber to prevent any side reactions.Reactions occurring in these chambers include the following:

1^(st) Chamber: MgCl₂•6H₂O → MgCl₂•4H₂O + 2H₂O 100° C. 2^(nd) Chamber:MgCl₂•4H₂O → MgCl₂•2H₂O + 2H₂O 125° C. 3^(rd) Chamber: MgCl₂•2H₂O →MgCl₂•H₂O + H₂O 160° C. (HCl vapor present) 4^(th) Chamber: MgCl₂•H₂O →Mg(OH)Cl + HCl 130° C. HCl recirculates to the 3^(rd) chamber. ModelPreferred Chamber Reaction Temp. Temp. Range Notes 1^(st)MgCl₂•6H₂O→MgCl₂•4H₂O + 100° C.  90° C.-120° C. 2H₂O 2^(nd)MgCl₂•4H₂O→MgCl₂•2H₂O + 125° C. 160° C.-185° C. 2H₂O 3^(rd) MgCl₂•2H₂O →MgCl₂•H₂O + 160° C. 190° C.-230° C. * H₂O 4^(th) MgCl₂•H₂O → Mg(OH)Cl +HCl 130° C. 230° C.-260° C. ** * HCl Vapor Present ** HCl VaporRecirculates to the 3^(rd) ChamberThe first three reactions above may be characterized as dehydrations,while the fourth may be characterized as a decomposition. Results fromthis simulation, which is explained in greater detail in Example 2,indicate that at lower temperatures (130-250° C.) the decomposition ofMgCl₂.6H₂O results in the formation of Mg(OH)Cl instead of MgO. TheMg(OH)Cl then reacts with H₂O to form MgCl₂ and Mg(OH)₂, which thenreacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas toform CaCO₃, which is filtered out of the stream. The resulting MgCl₂formed is recycled to the first reactor to begin the process again.

FIG. 7 is a process flow diagram showing parameters and results from aprocess simulation using Aspen Plus process software. The net reactionis the capture of CO₂ from flue gas using inexpensive raw materials,CaCl₂ and water, to form CaCO₃. In this embodiment, the magnesiumhexahydrate is dehydrated in two separate chambers and decomposed in athird chamber. Both dehydration and decomposition reactions occur in thethird chamber. There is no recirculating HCl. Reactions occurring inthese chambers include the following:

1^(st) Chamber: MgCl₂•6H₂O → MgCl₂•4H₂O + 2H₂O 100° C. 2^(nd) Chamber:MgCl₂•4H₂O → MgCl₂•2H₂O + 2H₂O 125° C. 3^(rd) Chamber: MgCl₂•2H₂O →Mg(OH)Cl + HCl + H₂O 130° C. 3^(rd) Chamber: MgCl₂•2H₂O → MgCl₂•H₂O +H₂O 130° C. Model Preferred Chamber Reaction Temp. Temp. Range Notes1^(st) MgCl₂•6H₂O→MgCl₂•4H₂O + 2H₂O 100° C.  90° C.-120° C. 2^(nd)MgCl₂•4H₂O→MgCl₂•2H₂O + 2H₂O 125° C. 160° C.-185° C. 3^(rd)MgCl₂•2H₂O→Mg(OH)Cl + HCl + 130° C. 190° C.-230° C. * H₂O MgCl₂•2H₂O →MgCl₂•H₂O + H₂O * No recirculating HClThe first, second and fourth reactions above may be characterized asdehydrations, while the third may be characterized as a decomposition.As in the embodiment of FIG. 6, the temperatures used in this embodimentresult in the formation of Mg(OH)Cl from the MgCl₂.6H₂O rather than MgO.The Mg(OH)Cl then reacts with H₂O to form MgCl₂ and Mg(OH)₂, whichreacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas toform CaCO₃, which is filtered out of the stream. The resulting MgCl₂formed is recycled to the first reactor to begin the process again.Additional details regarding this simulation are provided in Example 3below.

FIG. 8 is a process flow diagram showing parameters and results from aprocess simulation using Aspen Plus process software. The net reactionis the capture of CO₂ from flue gas using inexpensive raw materials,CaCl₂ and water, to form CaCO₃. Results from this simulation indicatethat it is efficient to heat MgCl₂.6H₂O to form MgO. The MgO then reactswith H₂O to form Mg(OH)₂, which then reacts with a saturated CaCl₂/H₂Osolution and CO₂ from the flue gas to form CaCO₃, which is filtered outof the stream. The resulting MgCl₂ formed is recycled to the firstreactor to begin the process again. In this embodiment, the magnesiumhexahydrate is simultaneously dehydrated and decomposed in one chamberat 450° C. This is the model termperature range. The preferred range insome emobodiments, is 450° C.-500° C. Thus the decomposition goescompletely to MgO. The main reaction occurring in this chamber can berepresented as follows:

MgCl₂.6H₂O→MgO+5H₂O+2HCl 450° C.

Additional details regarding this simulation are provided in Example 4below.

FIG. 9 is a process flow diagram showing parameters and results from aprocess simulation using Aspen Plus process software similar to theembodiment of FIG. 8 except that the MgCl₂.6H₂O is decomposed into anintermediate compound, Mg(OH)Cl at a lower temperature of 250° C. in onechamber. The Mg(OH)Cl is then dissolved in water to form MgCl₂ andMg(OH)₂, which follows through with the same reaction with CaCl₂ and CO₂to form CaCO₃ and MgCl₂. The main reaction occurring in this chamber canbe represented as follows:

MgCl₂.6H₂O→Mg(OH)Cl+HCl+5H₂O 250° C.

The reaction was modeled at 250° C. In some embodiments, the preferredrange is from 230° C. to 260° C. Additional details regarding thissimulation are provided in Example 5 below.

FIG. 10 shows a graph of the mass percentage of a heated sample ofMgCl₂.6H₂O. The sample's initial mass was approximately 70 mg and set at100%. During the experiment, the sample's mass was measured while it wasbeing thermally decomposed. The temperature was quickly ramped up to150° C., and then slowly increased by 0.5° C. per minute. Atapproximately 220° C., the weight became constant, consistent with theformation of Mg(OH)Cl.

FIG. 11 shows X-ray diffraction data corresponding to the product ofExample 7.

FIG. 12 shows X-ray diffraction data corresponding to the product fromthe reaction using Mg(OH)₂ of Example 8.

FIG. 13 shows X-ray diffraction data corresponding to the product fromthe reaction using Mg(OH)Cl of Example 8.

FIG. 14 shows the effect of temperature and pressure on thedecomposition of MgCl₂.(H₂O).

FIG. 15 is a process flow diagram of an embodiment of the Ca/Mg processdescribed herein.

FIG. 16 is a process flow diagram of a variant of the process, wherebyonly magnesium compounds are used. In this embodiment the Ca²⁺ —Mg²⁺switching reaction does not occur.

FIG. 17 is a process flow diagram of a different variant of the processwhich is in between the previous two embodiments. Half of the Mg²⁺ isreplaced by Ca²⁺, thereby making the resulting mineralized carbonateMgCa(CO₃)₂ or dolomite.

FIG. 18—CaSiO₃—Mg(OH)Cl Process, Cases 10 & 11. This figure shows aprocess flow diagram providing parameters and results from a processsimulation using Aspen Plus process software. The net reaction is thecapture of CO₂ from flue gas using inexpensive raw materials, CaSiO₃,CO₂ and water, to form SiO₂ and CaCO₃. Results from this simulationindicate that it is efficient to use heat from the HCl reacting withCaSiO₃ and heat from the flue gas emitted by a natural gas or coal firedpower plant to carry out the decomposition of MgCl₂.6H₂O to formMg(OH)Cl. The Mg(OH)Cl then reacts with H₂O to form MgCl₂ and Mg(OH)₂,which then reacts with a saturated CaCl₂/H₂O solution and CO₂ from theflue gas to form CaCO₃, which is filtered out of the stream. Theresulting MgCl₂ formed is recycled to the first reactor to begin theprocess again. In this embodiment, the magnesium chloride hexahydrate isdehydrated to magnesium chloride dihydrate MgCl₂.2H₂O in the firstchamber using heat from the HCl and CaSiO₃ reaction and decomposed in asecond chamber at 250° C. using heat from the flue gas. Thus thedecomposition goes partially to Mg(OH)Cl. The main reactions occurringin this chamber can be represented as follows:

ΔH** Reaction Reaction kJ/mole Temp. Range MgCl₂•6H₂O → Mg(OH)Cl +5H₂O + 433 230° C.-260° C. HCl 2HCl(g) + CaSiO₃ → CaCl₂(aq) + −259  90°C.-150° C. H₂O + SiO₂↓ 2Mg(OH)Cl + CO₂ + CaCl₂ → −266 25° C.-95° C.2MgCl₂ + CaCO₃↓ + H₂O **Enthalpies are based on reaction temperatures,and temperatures of incoming reactant and outgoing product streams.Additional details regarding this simulation are provided in Examples 10and 11 below.

FIG. 19—CaSiO₃—MgO Process, Cases 12 & 13. This figure shows a processflow diagram providing parameters and results from a process simulationusing Aspen Plus process software. The net reaction is the capture ofCO₂ from flue gas using inexpensive raw materials, CaSiO₃, CO₂ andwater, to form SiO₂ and CaCO₃. Results from this simulation indicatethat it is efficient to use heat from the HCl reacting with CaSiO₃ andheat from flue gas emitted by a natural gas or coal fired power plant tocarry out the decomposition of MgCl₂.6H₂O to form MgO. The MgO thenreacts with H₂O to form Mg(OH)₂, which then reacts with a saturatedCaCl₂/H₂O solution and CO₂ from the flue gas to form CaCO₃, which isfiltered out of the stream. The resulting MgCl₂ formed is recycled tothe first reactor to begin the process again. In this embodiment, themagnesium chloride hexahydrate is dehydrated to magnesium chloridedihydrate MgCl₂.2H₂O in the first chamber using heat from the HCl andCaSiO₃ reaction and decomposed in a second chamber at 450° C. using heatfrom the flue gas. Thus the decomposition goes completely to MgO. Themain reactions occurring in this chamber can be represented as follows:

ΔH Reaction Reaction kJ/mole** Temp. Range MgCl₂•6H₂O → MgO + 5H₂O + 560450° C.-500° C. 2HCl 2HCl(g) + CaSiO₃ → CaCl₂(aq) + −264  90° C.-150° C.H₂O + SiO₂↓ MgO + CO₂ + CaCl₂(aq) → −133 25° C.-95° C. MgCl₂(aq) +CaCO₃↓ **Enthalpies are based on reaction temperatures, and temperaturesof incoming reactant and outgoing product streams. Additional detailsregarding this simulation are provided in Examples 12 and 13 below.

FIG. 20—MgSiO₃—Mg(OH)Cl Process, Cases 14 & 15. This figure shows aprocess flow diagram providing parameters and results from a processsimulation using Aspen Plus process software. The net reaction is thecapture of CO₂ from flue gas using inexpensive raw materials, MgSiO₃,CO₂ and water, to form SiO₂ and MgCO₃. Results from this simulationindicate that it is efficient to use heat from the HCl reacting withMgSiO₃ and heat from the flue gas emitted by a natural gas or coal firedpower plant to carry out the decomposition of MgCl₂.2H₂O to formMg(OH)Cl. The Mg(OH)Cl then reacts with H₂O to form MgCl₂ and Mg(OH)₂,which then reacts with CO₂ from the flue gas to form MgCO₃, which isfiltered out of the stream. The resulting MgCl₂ formed is recycled tothe first reactor to begin the process again. In this embodiment, themagnesium chloride remains in the dihydrate form MgCl₂.2H₂O due to theheat from the HCl and MgSiO₃ prior to decomposition at 250° C. usingheat from the flue gas. Thus the decomposition goes partially toMg(OH)Cl. The main reactions occurring in this chamber can berepresented as follows:

ΔH Reaction Reaction kJ/mole ** Temp. Ranges MgCl₂•2H₂O → Mg(OH)Cl +139.8 230° C.-260° C. H₂O(g) + HCl(g) 2HCl(g) + MgSiO₃ → MgCl₂ + −282.8 90° C.-150° C. H₂O + SiO₂↓ 2Mg(OH)Cl + CO₂ → MgCl₂ + −193.1 25° C.-95°C. MgCO₃↓ + H₂O ** Enthalpies are based on reaction temperatures, andtemperatures of incoming reactant and outgoing product streams.Additional details regarding this simulation are provided in Examples 14and 15 below.

FIG. 21—MgSiO₃—MgO Process, Cases 16 & 17. This figure shows a processflow diagram providing parameters and results from a process simulationusing Aspen Plus process software. The net reaction is the capture ofCO₂ from flue gas using inexpensive raw materials, MgSiO₃, CO₂ andwater, to form SiO₂ and MgCO₃. Results from this simulation indicatethat it is efficient to use heat from the HCl reacting with MgSiO₃ andheat from the flue gas emitted by a natural gas or coal fired powerplant to carry out the decomposition of MgCl₂.2H₂O to form MgO. The MgOthen reacts with H₂O to form Mg(OH)₂, which then reacts with CO₂ fromthe flue gas to form MgCO₃, which is filtered out of the stream. In thisembodiment, the magnesium chloride remains in the dihydrate formMgCl₂.2H₂O due to the heat from the HCl and MgSiO₃ prior todecomposition at 450° C. using heat from the flue gas. Thus thedecomposition goes completely to MgO. The main reactions occurring inthis chamber can be represented as follows:

ΔH Reaction Reaction kJ/mole ** Temp. Range MgCl₂•2H₂O → MgO + H₂O(g) +232.9 450° C.-500° C. 2HCl(g) 2HCl(g) + MgSiO₃ → MgCl₂(aq) + −293.5  90°C.-150° C. H₂O(g) + SiO₂↓ MgO + CO₂ → MgCO₃↓ −100 25° C.-95° C. **Enthalpies are based on reaction temperatures, and temperatures ofincoming reactant and outgoing product streams. Additional detailsregarding this simulation are provided in Examples 16 and 17 below.

FIG. 22—Diopside-Mg(OH)Cl Process, Cases 18 & 19. This figure shows aprocess flow diagram providing parameters and results from a processsimulation using Aspen Plus process software. The net reaction is thecapture of CO₂ from flue gas using inexpensive raw materials, diopsideMgCa(SiO₃)₂, CO₂ and water, to form SiO₂ and dolomite MgCa(CO₃)₂.Results from this simulation indicate that it is efficient to use heatfrom the HCl reacting with MgCa(SiO₃)₂ and heat from the flue gasemitted by a natural gas or coal fired power plant to carry out thedecomposition of MgCl₂.6H₂O to form Mg(OH)Cl. The Mg(OH)Cl then reactswith H₂O to form MgCl₂ and Mg(OH)₂, which then reacts with a saturatedCaCl₂/H₂O solution and CO₂ from the flue gas to form MgCa(CO₃)₂ which isfiltered out of the stream. The resulting MgCl₂ formed is recycled tothe first reactor to begin the process again. In this embodiment, themagnesium chloride hexahydrate is dehydrated to magnesium chloridedihydrate MgCl₂.2H₂O in the first chamber using heat from the HCl andCaSiO₃ reaction and decomposed to Mg(OH)Cl in a second chamber at 250°C. using heat from the flue gas. The main reactions occurring in thischamber can be represented as follows:

ΔH Reaction Reaction kJ/mole** Temp. Range MgCl₂•6H₂O → Mg(OH)Cl +5H₂O(g) + 433 230° C.-260° C. HCl(g) 2HCl(g) + MgCa(SiO₃)₂ → CaCl₂(aq) +−235  90° C.-150° C. MgSiO₃↓ + SiO₂↓ + H₂O 2HCl(g) + MgSiO₃ →MgCl₂(aq) + −282.8  90° C.-150° C. SiO₂↓ + H₂O 4Mg(OH)Cl + 2CO₂ +CaCl₂(aq) → −442 25° C.-95° C. MgCa(CO₃)₂↓ + 3MgCl₂(aq) + 2H₂O**Enthalpies are based on reaction temperatures, and temperatures ofincoming reactant and outgoing product streams. Additional detailsregarding this simulation are provided in Examples 18 and 19 below.

FIG. 23—Diopside-MgO Process, Cases 20 & 21. This figure shows a processflow diagram providing parameters and results from a process simulationusing Aspen Plus process software. The net reaction is the capture ofCO₂ from flue gas using inexpensive raw materials, diopside MgCa(SiO₃)₂,CO₂ and water, to form SiO₂ and dolomite MgCa(CO₃)₂. Results from thissimulation indicate that it is efficient to use heat from the HClreacting with MgCa(SiO₃)₂ and heat from the flue gas emitted by anatural gas or coal fired power plant and/or other heat source to carryout the decomposition of MgCl₂.6H₂O to form MgO. The MgO then reactswith H₂O to form Mg(OH)₂, which then reacts with a saturated CaCl₂/H₂Osolution and CO₂ from the flue gas to form MgCa(CO₃)₂ which is filteredout of the stream. The resulting MgCl₂ formed is recycled to the firstreactor to begin the process again. In this embodiment, the magnesiumchloride hexahydrate is dehydrated to magnesium chloride dihydrateMgCl₂.2H₂O in the first chamber using heat from the HCl and CaSiO₃reaction and decomposed to MgO in a second chamber at 450° C. using heatfrom the flue gas. The main reactions occurring in this chamber can berepresented as follows:

ΔH Reaction Reaction kJ/mole** Temp. Range MgCl₂•6H₂O → MgO + 5H₂O +2HCl 560 450° C.-500° C. 2HCl(g) + MgCa(SiO₃)₂ → CaCl₂(g) + −240  90°C.-150° C. MgSiO₃↓ + SiO₂↓ + H₂O 2HCl(aq) + MgSiO₃ → MgCl₂(aq) + −288 90° C.-150° C. SiO₂↓ + H₂O 2MgO + 2CO₂ + CaCl₂(aq) → −258 25° C.-95° C.MgCa(CO₃)₂↓ + MgCl₂(aq) **Enthalpies are based on reaction temperatures,and temperatures of incoming reactant and outgoing product streams.Additional details regarding this simulation are provided in Examples 20and 21 below.

FIG. 24 illustrates the percent CO₂ captured for varying CO₂ flue gasconcentrations, varying temperatures, whether the flue gas wasoriginated from coal or natural gas, and also whether the process reliedon full or partial decomposition. See Examples 10 through 13 of theCaSiO₃—Mg(OH)Cl and CaSiO₃—MgO processes.

FIG. 25 illustrates the percent CO₂ captured for varying CO₂ flue gasconcentrations, varying temperatures, whether the flue gas wasoriginated from coal or natural gas, and also whether the process reliedon full or partial decomposition. See Examples 14 through 17 of theMgSiO₃—Mg(OH)Cl and MgSiO₃—MgO processes.

FIG. 26 illustrates the percent CO₂ captured for varying CO₂ flue gasconcentrations, varying temperatures, whether the flue gas wasoriginated from coal or natural gas, and also whether the process reliedon full or partial decomposition. See Examples 18 through 21 of theDiopside—Mg(OH)Cl and Diopside—MgO processes.

FIG. 27 is a simplified process-flow diagram corresponding to someembodiments of the present invention in which two different salts, e.g.,Ca²⁺ and Mg²⁺, are used for decomposition and carbonation.

FIGS. 28-29 show graphs of the mass percentages of heated samples ofMgCl₂.6H₂O. The initial masses of the samples were approximately 70 mgeach and were each set at 100%. During the experiment, the masses of thesamples were measured while they was being thermally decomposed. Thetemperature was ramped up to 200° C. then further increased over thecourse of a 12 hour run. The identities of the decomposed materials canbe confirmed by comparing against the theoretical plateaus provided.FIG. 28 is a superposition of two plots, the first one being the solidline, which is a plot of time (minutes) versus temperature (° C.). Theline illustrates the ramping of temperature over time; the second plot,being the dashed line is a plot of weight % (100%=original weight ofsample) versus time, which illustrates the reduction of the sample'sweight over time whether by dehydration or decomposition. FIG. 29 isalso a superposition of two plots, the first (the solid line) is a plotof weight % versus temperature (° C.), illustrating the sample's weightdecreasing as the temperature increases; the second plot (the dashedline) is a plot of the derivative of the weight % with respect totemperature (wt. %/° C.) versus temperature ° C. When this value is highit indicates a higher rate of weight loss for each change per degree. Ifthis value is zero, the sample's weight remains the same although thetemperature is increasing, indicating an absence of dehydration ordecomposition. Note FIGS. 28 and 29 are of the same sample.

FIG. 30—MgCl₂.6H₂O Decomposition at 500° C. after One Hour. This graphshows the normalized final and initial weights of four test runs ofMgCl₂.6H₂O after heating at 500° C. for one hour. The consistent finalweight confirms that MgO is made by decomposition at this temperature.

FIG. 31—Three-Chamber Decomposition. This figure shows a process flowdiagram providing parameters and results from a process simulation usingAspen Plus process software. In this embodiment, heat from cold flue gas(chamber 1), heat from mineral dissolution reactor (chamber 2), andexternal natural gas (chamber 3) are used as heat sources. This processflow diagram illustrates a three chamber process for the decompositionto Mg(OH)Cl. The first chamber is heated by 200° C. flue gas to providesome initial heat about ˜8.2% of the total required heat, the secondchamber which relies on heat recovered from the mineral dissolutionreactor to provide 83% of the needed heat for the decomposition of which28% is from the hydrochloric acid/mineral silicate reaction and 55% isfrom the condensation and formation of hydrochloric acid, and finallythe third chamber, which uses natural gas as an external source of theremaining heat which is 8.5% of the total heat. The CO₂ is from acombined cycle power natural gas plant, so very little heat is availablefrom the power plant to power the decomposition reaction.

FIG. 32—Four-Chamber Decomposition. This figure shows a process flowdiagram providing parameters and results from a process simulation usingAspen Plus process software. In this embodiment, heat from cold flue gas(chamber 1), heat from additional steam (chamber 2), heat from mineraldissolution reactor (chamber 3), and external natural gas (chamber 4)are used as heat sources. This process flow diagram illustrates a fourchamber process for the decomposition to Mg(OH)Cl, the first chamberprovides 200° C. flue gas to provide some initial heat about ˜8.2% ofthe total required heat, the second chamber provides heat in the form ofextra steam which is 0.8% of the total heat needed, the third chamberwhich relies on heat recovered from the mineral dissolution reactor toprovide 83% of the needed heat for the decomposition of which 28% isfrom the hydrochloric acid/mineral silicate reaction and 55% is from thecondensation and formation of hydrochloric acid, and finally the fourthchamber, which uses natural gas as an external source of the remainingheat which is 8.0% of the total heat. The CO₂ is from a combined cyclenatural gas power plant, so very little heat is available from the powerplant to power the decomposition reaction.

FIG. 33—Two-Chamber Decomposition. This figure shows a process flowdiagram providing parameters and results from a process simulation usingAspen Plus process software. In this embodiment, heat from mineraldissolution reactor (chamber 1), and external natural gas (chamber 2)are used as heat sources. This process flow diagram illustrates a twochamber process for the decomposition to Mg(OH)Cl, the first chamberwhich relies on heat recovered from the mineral dissolution reactor toprovide 87% of the needed heat for the decomposition of which 28% isfrom the hydrochloric acid/mineral silicate reaction and 59% is from thecondensation and formation of hydrochloric acid, and the second chamber,which uses natural gas as an external source of the remaining heat whichis 13% of the total heat. The CO₂ is from a combined cycle natural gaspower plant, so very little heat is available from the power plant topower the decomposition reaction.

FIG. 34—Two-Chamber Decomposition. This figure shows a process flowdiagram providing parameters and results from a process simulation usingAspen Plus process software. In this embodiment, heat from mineraldissolution reactor (chamber 1), and hot flue gas from open cyclenatural gas plant (chamber 2) are used as heat sources. This processflow diagram illustrates a two chamber process for the decomposition toMg(OH)Cl, the first chamber which relies on heat recovered from themineral dissolution reactor to provide 87% of the needed heat for thedecomposition of which 28% is from the hydrochloric acid/mineralsilicate reaction and 59% is from the condensation and formation ofhydrochloric acid, and the second chamber, which uses hot flue gas as anexternal source of the remaining heat which is 13% of the total heat.The CO₂ is from an open cycle natural gas power plant, thereforesubstantial heat is available from the power plant in the form of 600°C. flue gas to power the decomposition reaction.

FIG. 35 shows a schematic diagram of a Auger reactor which may be usedfor the salt decomposition reaction, including the decomposition ofMgCl₂.6H₂O to M(OH)Cl or MgO. Such reactors may comprises internalheating for efficient heat utilization, external insulation forefficient heat utilization, a screw mechanism for adequate solidtransport (when solid is present), adequate venting for HCl removal.Such a reactors has been used to prepare ˜1.8 kg of ˜90% Mg(OH)Cl.

FIG. 36 shows the optimization index for two separate runs of makingMg(OH)Cl using an Auger reactor. The optimization index=% conversion×%efficiency.

FIG. 37 shows a process flow diagram of an Aspen model that simulates anCaSiO₃—Mg(OH)Cl Process.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention relates to carbon dioxide sequestration, includingenergy-efficient processes in which Group 2 chlorides are converted toGroup 2 hydroxides and hydrogen chloride, which are then used to removecarbon dioxide from waste streams. In some embodiments, hydrogenchloride may be further reacted with Group 2 silicates to produceadditional Group 2 chloride starting materials and silica.

In some embodiments, the methods and apparatuses of the inventioncomprise one or more of the following general components: (1) theconversion of Group 2 silicate minerals with hydrogen chloride intoGroup 2 chlorides and silicon dioxide, (2) conversion of Group 2chlorides into Group 2 hydroxides and hydrogen chloride, (3) an aqueousdecarbonation whereby gaseous CO₂ is absorbed into an aqueous causticmixture comprising Group 2 hydroxides to form Group 2 carbonate and/orbicarbonate products and water, (4) a separation process whereby thecarbonate and/or bicarbonate products are separated from the liquidmixture, (5) the reuse or cycling of by-products, including energy, fromone or more of the steps or process streams into another one or moresteps or process streams. Each of these general components is explainedin further detail below.

While many embodiments of the present invention consume some energy toaccomplish the absorption of CO₂ and other chemicals from flue-gasstreams and to accomplish the other objectives of embodiments of thepresent invention as described herein, one advantage of certainembodiments of the present invention is that they provide ecologicalefficiencies that are superior to those of the prior art, whileabsorbing most or all of the emitted CO₂ from a given source, such as apower plant.

Another additional benefit of certain embodiments of the presentinvention that distinguishes them from other CO₂-removal processes isthat in some market conditions, the products are worth considerably morethan the reactants required or the net-power or plant-depreciationcosts. In other words, certain embodiments are industrial methods ofproducing chloro-hydro-carbonate products at a profit, whileaccomplishing considerable removal of CO₂ and incidental pollutants ofconcern.

I. DEFINITIONS

As used herein, the terms “carbonates” or “carbonate products” aregenerally defined as mineral components containing the carbonate group,[CO₃]²⁻. Thus, the terms encompass both carbonate/bicarbonate mixturesand species containing solely the carbonate ion. The terms“bicarbonates” and “bicarbonate products” are generally defined asmineral components containing the bicarbonate group, [HCO₃]¹⁻. Thus, theterms encompass both carbonate/bicarbonate mixtures and speciescontaining solely the bicarbonate ion.

As used herein “Ca/Mg” signifies either Ca alone, Mg alone or a mixtureof both Ca and Mg. The ratio of Ca to Mg may range from 0:100 to 100:0,including, e.g., 1:99, 5:95, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40,70:30, 80:20, 90:10, 95:5, and 99:1. The symbols “Ca/Mg”,“Mg_(x)Ca_((1-x))” and Ca_(x)Mg_((1-x))” are synonymous. In contrast,“CaMg” or “MgCa” refers to a 1:1 ratio of these two ions.

As used herein, the term “ecological efficiency” is used synonymouslywith the term “thermodynamic efficiency” and is defined as the amount ofCO₂ sequestered by certain embodiments of the present invention perenergy consumed (represented by the equation “∂CO₂/∂E”), appropriateunits for this value are kWh/ton CO₂. CO₂ sequestration is denominatedin terms of percent of total plant CO₂; energy consumption is similarlydenominated in terms of total plant power consumption.

The terms “Group II” and “Group 2” are used interchangeably.

“Hexahydrate” refers to MgCl₂.6H₂O.

In the formation of bicarbonates and carbonates using some embodimentsof the present invention, the term “ion ratio” refers to the ratio ofcations in the product divided by the number of carbons present in thatproduct. Hence, a product stream formed of calcium bicarbonate(Ca(HCO₃)₂) may be said to have an “ion ratio” of 0.5 (Ca/C), whereas aproduct stream formed of pure calcium carbonate (CaCO₃) may be said tohave an “ion ratio” of 1.0 (Ca/C). By extension, an infinite number ofcontinuous mixtures of carbonate and bicarbonate of mono-, di- andtrivalent cations may be said to have ion ratios varying between 0.5 and3.0.

Based on the context, the abbreviation “MW” either means molecularweight or megawatts.

The abbreviation “PFD” is process flow diagram.

The abbreviation “Q” is heat (or heat duty), and heat is a type ofenergy. This does not include any other types of energy.

As used herein, the term “sequestration” is used to refer generally totechniques or practices whose partial or whole effect is to remove CO₂from point emissions sources and to store that CO₂ in some form so as toprevent its return to the atmosphere. Use of this term does not excludeany form of the described embodiments from being considered“sequestration” techniques.

In the context of a chemical formula, the abbreviation “W” refers toH₂O.

The pyroxenes are a group of silicate minerals found in many igneous andmetamorphic rocks. They share a common structure consisting of singlechains of silica tetrahedra and they crystallize in the monoclinic andorthorhombic systems. Pyroxenes have the general formula XY(Si,Al)₂O₆,where X represents calcium, sodium, iron (II) and magnesium and morerarely zinc, manganese and lithium and Y represents ions of smallersize, such as chromium, aluminium, iron(III), magnesium, manganese,scandium, titanium, vanadium and even iron (II).

In addition, atoms making up the compounds of the present invention areintended to include all isotopic forms of such atoms. Isotopes, as usedherein, include those atoms having the same atomic number but differentmass numbers. By way of general example and without limitation, isotopesof hydrogen include tritium and deuterium, and isotopes of carboninclude ¹³C and ¹⁴C.

The use of the word “a” or “an,” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.”

Throughout this application, the term “about” is used to indicate that avalue includes the inherent variation of error for the device, themethod being employed to determine the value, or the variation thatexists among the study subjects.

The terms “comprise,” “have” and “include” are open-ended linking verbs.Any forms or tenses of one or more of these verbs, such as “comprises,”“comprising,” “has,” “having,” “includes” and “including,” are alsoopen-ended. For example, any method that “comprises,” “has” or“includes” one or more steps is not limited to possessing only those oneor more steps and also covers other unlisted steps.

The term “effective,” as that term is used in the specification and/orclaims, means adequate to accomplish a desired, expected, or intendedresult.

The above definitions supersede any conflicting definition in any of thereference that is incorporated by reference herein. The fact thatcertain terms are defined, however, should not be considered asindicative that any term that is undefined is indefinite. Rather, allterms used are believed to describe the invention in terms such that oneof ordinary skill can appreciate the scope and practice the presentinvention.

II. SEQUESTRATION OF CARBON DIOXIDE USING SALTS OF GROUP II METALS

FIG. 1 depicts a simplified process-flow diagram illustrating general,exemplary embodiments of the apparatuses and methods of the presentdisclosure. This diagram is offered for illustrative purposes only, andthus it merely depicts specific embodiments of the present invention andis not intended to limit the scope of the claims in any way.

In the embodiment shown in FIG. 1, reactor 10 (e.g., a road salt boiler)uses power, such as external power and/or recaptured power (e.g., heatfrom hot flue gas or an external source of heat such as solarconcentration or combustion), to drive a reaction represented byequation 1.

(Ca/Mg)Cl₂+2H₂O→(Ca/Mg)(OH)₂+2HCl  (1)

The water used in this reaction may be in the form of liquid, steam, acrystalline hydrate, e.g., MgCl₂.6H₂O, CaCl₂.2H₂O, or it may besupercritical. In some embodiments, the reaction uses MgCl₂ to formMg(OH)₂ and/or Mg(OH)Cl (see, e.g., FIG. 2). In some embodiments, thereaction uses CaCl₂ to form Ca(OH)₂. Some or all of the Group 2hydroxide or hydroxychloride (not shown) from equation 1 may bedelivered to reactor 20. In some embodiments, some or all of the Group 2hydroxide and/or Group 2 hydroxychloride is delivered to reactor 20 asan aqueous solution. In some embodiments, some or all of the Group 2hydroxide is delivered to reactor 20 in an aqueous suspension. In someembodiments, some or all of the Group 2 hydroxide is delivered toreactor 20 as a solid. In some embodiments, some or all of the hydrogenchloride (e.g., in the form of vapor or in the form of hydrochloricacid) may be delivered to reactor 30 (e.g., a rock melter). In someembodiments, the resulting Group 2 hydroxides are further heated toremove water and form corresponding Group 2 oxides. In some variants,some or all of these Group 2 oxides may then be delivered to reactor 20.

Carbon dioxide from a source, e.g., flue-gas, enters the process atreactor 20 (e.g., a fluidized bed reactor, a spray-tower decarbonator ora decarbonation bubbler), potentially after initially exchangingwaste-heat with a waste-heat/DC generation system. In some embodimentsthe temperature of the flue gas is at least 125° C. The Group 2hydroxide, some or all of which may be obtained from reactor 10, reactswith carbon dioxide in reactor 20 according to the reaction representedby equation 2.

(Ca/Mg)(OH)₂+CO₂→(Ca/Mg)CO₃+H₂O  (2)

The water produced from this reaction may be delivered back to reactor10. The Group 2 carbonate is typically separated from the reactionmixture. Group 2 carbonates have a very low K_(sp) (solubility productconstant). So they be separated as solids from other, more solublecompounds that can be kept in solution. In some embodiments, thereaction proceeds through Group 2 bicarbonate salts. In someembodiments, Group 2 bicarbonate salts are generated and optionally thenseparated from the reaction mixture. In some embodiments, Group 2oxides, optionally together with or separately from the Group 2hydroxides, are reacted with carbon dioxide to also form Group 2carbonate salts. In some embodiments, the flue gas, from which CO₂and/or other pollutants have been removed, is released to the air.

Group 2 silicates (e.g., CaSiO₃, MgSiO₃, MgO.FeO.SiO₂, etc.) enter theprocess at reactor 30 (e.g., a rock melter or a mineral dissociationreactor). In some embodiments, these Group 2 silicates are ground in aprior step. In some embodiments, the Group 2 silicates are inosilicates.These minerals may be reacted with hydrochloric acid, either as a gas orin the form of hydrochloric acid, some or all of which may be obtainedfrom reactor 10, to form the corresponding Group 2 metal chlorides(CaCl₂ and/or MgCl₂), water and sand (SiO₂). The reaction can berepresented by equation 3.

2HCl+(Ca/Mg)SiO₃→(Ca/Mg)Cl₂+H₂O+SiO₂  (3)

Some or all of the water produced from this reaction may be delivered toreactor 10. Some or all of the Group 2 chlorides from equation 3 may bedelivered to reactor 20. In some embodiments, some or all of the Group 2chloride is delivered to reactor 20 as an aqueous solution. In someembodiments, some or all of the Group 2 chloride is delivered to reactor20 in an aqueous suspension. In some embodiments, some or all of theGroup 2 chloride is delivered to reactor 20 as a solid.

The net reaction capturing the summation of equations 1-3 is shown hereas equation 4:

CO₂+(Ca/Mg)SiO₃→(Ca/Mg)CO₃+SiO₂  (4)

In another embodiment, the resulting Mg_(x)Ca_((1-x))CO₃ sequestrant isreacted with HCl in a manner to regenerate and concentrate the CO₂. TheCa/MgCl₂ thus formed is returned to the decomposition reactor to produceCO₂ absorbing hydroxides or hydroxyhalides.

Through the process shown in FIG. 1 and described herein, Group 2carbonates are generated as end-sequestrant material from the capturedCO₂. Some or all of the water, hydrogen chloride and/or reaction energymay be cycled. In some embodiments, only some or none of these arecycled. In some embodiments, the water, hydrogen chloride and reactionenergy made be used for other purposes.

In some embodiments, and depending on the concentration of CO₂ in theflue gas stream of a given plant, the methods disclosed herein may beused to capture 33-66% of the plant's CO₂ using heat-only as the driver(no electrical penalty). In some embodiments, the efficiencies of themethods disclosed herein improve with lower CO₂-concentrations, andincrease with higher (unscrubbed) flue-gas temperatures. For example, at320° C. and 7% CO₂ concentration, 33% of flue-gas CO₂ can be mineralizedfrom waste-heat alone. In other embodiments, e.g., at the exittemperatures of natural gas turbines approximately 100% mineralizationcan be achieved.

These methods and devices can be further modified, e.g., with modularcomponents, optimized and scaled up using the principles and techniquesof chemistry, chemical engineering, and/or materials science as appliedby a person skilled in the art. Such principles and techniques aretaught, for example, in U.S. Pat. No. 7,727,374, U.S. Patent ApplicationPublications 2006/0185985 and 2009/0127127, U.S. patent application Ser.No. 11/233,509, filed Sep. 22, 2005, U.S. Provisional Patent ApplicationNo. 60/718,906, filed Sep. 20, 2005; U.S. Provisional Patent ApplicationNo. 60/642,698, filed Jan. 10, 2005; U.S. Provisional Patent ApplicationNo. 60/612,355, filed Sep. 23, 2004, U.S. patent application Ser. No.12/235,482, filed Sep. 22, 2008, U.S. Provisional Application No.60/973,948, filed Sep. 20, 2007, U.S. Provisional Application No.61/032,802, filed Feb. 29, 2008, U.S. Provisional Application No.61/033,298, filed Mar. 3, 2008, U.S. Provisional Application No.61/288,242, filed Jan. 20, 2010, U.S. Provisional Application No.61/362,607, filed Jul. 8, 2010, and International Application No.PCT/US08/77122, filed Sep. 19, 2008. The entire text of each of theabove-referenced disclosures (including any appendices) is specificallyincorporated by reference herein.

The above examples were included to demonstrate particular embodimentsof the invention. However, those of skill in the art should, in light ofthe present disclosure, appreciate that many changes can be made in thespecific embodiments which are disclosed and still obtain a like orsimilar result without departing from the spirit and scope of theinvention.

III. SEQUESTRATION OF CARBON DIOXIDE USING Mg²⁺ AS CATALYST

FIG. 2 depicts a simplified process-flow diagram illustrating general,exemplary embodiments of the apparatuses and methods of the presentdisclosure. This diagram is offered for illustrative purposes only, andthus it merely depicts specific embodiments of the present invention andis not intended to limit the scope of the claims in any way.

In the embodiment shown in FIG. 2, reactor 100 uses power, such asexternal power and/or recaptured power (e.g., heat from hot flue gas),to drive a decomposition-type reaction represented by equation 5.

MgCl₂ .x(H₂O)+yH₂O→z′[Mg(OH)₂]+z″[MgO]+z′″[MgCl(OH)]+(2z′+2z″+z′″)[HCl]  (5)

The water used in this reaction may be in the form of a hydrate ofmagnesium chloride, liquid, steam and/or it may be supercritical. Insome embodiments, the reaction may occur in one, two, three or morereactors. In some embodiments, the reaction may occur as a batch,semi-batch of continuous process. In some embodiments, some or all ofthe magnesium salt product may be delivered to reactor 200. In someembodiments, some or all of the magnesium salt product is delivered toreactor 200 as an aqueous solution. In some embodiments, some or all ofthe magnesium salt product is delivered to reactor 200 in an aqueoussuspension. In some embodiments, some or all of the magnesium saltproduct is delivered to reactor 200 as a solid. In some embodiments,some or all of the hydrogen chloride (e.g., in the form of vapor or inthe form of hydrochloric acid) may be delivered to reactor 300 (e.g., arock melter). In some embodiments, the Mg(OH)₂ is further heated toremove water and form MgO. In some embodiments, the MgCl(OH) is furtherheated to remove HCl and form MgO. In some variants, one or more ofMg(OH)₂, MgCl(OH) and MgO may then be delivered to reactor 200.

Carbon dioxide from a source, e.g., flue-gas, enters the process atreactor 200 (e.g., a fluidized bed reactor, a spray-tower decarbonatoror a decarbonation bubbler), potentially after initially exchangingwaste-heat with a waste-heat/DC generation system. In some embodimentsthe temperature of the flue gas is at least 125° C. Admixed with thecarbon dioxide is the magnesium salt product from reactor 100 and CaCl₂(e.g., rock salt). The carbon dioxide reacts with the magnesium saltproduct and CaCl₂ in reactor 200 according to the reaction representedby equation 6.

CO₂+CaCl₂ +z′[Mg(OH)₂]+z″[MgO]+z′″[MgCl(OH)]→(z′+z″+z′″)MgCl₂+(z′+½z′″)H₂O+CaCO₃  (6)

In some embodiments, the water produced from this reaction may bedelivered back to reactor 100. The calcium carbonate product (e.g.,limestone, calcite) is typically separated (e.g., through precipitation)from the reaction mixture. In some embodiments, the reaction proceedsthrough magnesium carbonate and bicarbonate salts. In some embodiments,the reaction proceeds through calcium bicarbonate salts. In someembodiments, various Group 2 bicarbonate salts are generated andoptionally then separated from the reaction mixture. In someembodiments, the flue gas, from which CO₂ and/or other pollutants havebeen removed, is released to the air, optionally after one or morefurther purification and/or treatment steps. In some embodiments, theMgCl₂ product, optionally hydrated, is returned to reactor 100. In someembodiments, the MgCl₂ product is subjected to one or more isolation,purification and/or hydration steps before being returned to reactor100.

Calcium silicate (e.g., 3CaO.SiO₂, Ca₃SiO₅; 2CaO.SiO₂, Ca₂SiO₄;3Ca.2SiO₂, Ca₃Si₂O₇ and CaO.SiO₂, CaSiO₃ enters the process at reactor300 (e.g., a rock melter). In some embodiments, these Group 2 silicatesare ground in a prior step. In some embodiments, the Group 2 silicatesare inosilicates. In the embodiment of FIG. 2, the inosilicate is CaSiO₃(e.g., wollastonite, which may itself, in some embodiments, containsmall amounts of iron, magnesium and/or manganese substituting foriron). The CaSiO₃ is reacted with hydrogen chloride, either gas or inthe form of hydrochloric acid, some or all of which may be obtained fromreactor 100, to form CaCl₂, water and sand (SiO₂). The reaction can berepresented by equation 7.

2HCl+(Ca/Mg)SiO₃→(Ca/Mg)Cl₂+H₂O+SiO₂  (7)

ΔH Reaction Reaction kJ/mole** Temp. Range 2 HCl(g) + CaSiO₃ → CaCl₂ +H₂O + −254 90° C.-150° C. SiO₂ 2 HCl(g) + MgSiO₃ → MgCl₂(aq) + −288 90°C.-150° C. H₂O + SiO₂ **Enthalpies are based on reaction temperatures,and temperatures of incoming reactant and outgoing product streams. Someor all of the water produced from this reaction may be delivered toreactor 100. Some or all of the CaCl₂ from equation 7 may be deliveredto reactor 200. In some embodiments, some or all of the CaCl₂ isdelivered to reactor 200 as an aqueous solution. In some embodiments,some or all of the CaCl₂ is delivered to reactor 200 in an aqueoussuspension. In some embodiments, some or all of the CaCl₂ is deliveredto reactor 200 as a solid.

The net reaction capturing the summation of equations 5-7 is shown hereas equation 8:

CO₂+CaSiO₃→CaCO₃+SiO₂  (8)

Reaction ΔH kJ/mole** ΔG kJ/mole** CO₂ + CaSiO₃ → CaCO₃ + SiO₂ −89 −39**Measured at standard temperature and pressure (STP). Through theprocess shown in FIG. 2 and described herein, calcium carbonates aregenerated as end-sequestrant material from CO₂ and calcium inosilicate.Some or all of the various magnesium salts, water, hydrogen chloride andreaction energy may be cycled. In some embodiments, only some or none ofthese are cycled. In some embodiments, the water, hydrogen chlorideand/or reaction energy made be used for other purposes.

These methods and devices can be further modified, optimized and scaledup using the principles and techniques of chemistry, chemicalengineering, and/or materials science as applied by a person skilled inthe art. Such principles and techniques are taught, for example, in U.S.Pat. No. 7,727,374, U.S. Patent Application Publications 2006/0185985and 2009/0127127, U.S. patent application Ser. No. 11/233,509, filedSep. 22, 2005, U.S. Provisional Patent Application No. 60/718,906, filedSep. 20, 2005; U.S. Provisional Patent Application No. 60/642,698, filedJan. 10, 2005; U.S. Provisional Patent Application No. 60/612,355, filedSep. 23, 2004, U.S. patent application Ser. No. 12/235,482, filed Sep.22, 2008, U.S. Provisional Application No. 60/973,948, filed Sep. 20,2007, U.S. Provisional Application No. 61/032,802, filed Feb. 29, 2008,U.S. Provisional Application No. 61/033,298, filed Mar. 3, 2008, U.S.Provisional Application No. 61/288,242, filed Jan. 20, 2010, U.S.Provisional Application No. 61/362,607, filed Jul. 8, 2010, andInternational Application No. PCT/US08/77122, filed Sep. 19, 2008. Theentire text of each of the above-referenced disclosures (including anyappendices) is specifically incorporated by reference herein.

The above examples were included to demonstrate particular embodimentsof the invention. However, those of skill in the art should, in light ofthe present disclosure, appreciate that many changes can be made in thespecific embodiments which are disclosed and still obtain a like orsimilar result without departing from the spirit and scope of theinvention.

IV. CONVERSION OF GROUP 2 CHLORIDES INTO GROUP 2 HYDROXIDES OR GROUP IIHYDROXY CHLORIDES

Disclosed herein are processes that react a Group 2 chloride, e.g.,CaCl₂ or MgCl₂, with water to form a Group 2 hydroxide, a Group 2 oxide,and/or a mixed salt such as a Group 2 hydroxide chloride. Such reactionsare typically referred to as decompositions. In some embodiments, thewater may be in the form of liquid, steam, from a hydrate of the Group 2chloride, and/or it may be supercritical. The steam may come from a heatexchanger whereby heat from an immensely combustible reaction, i.e.natural gas and oxygen or hydrogen and chlorine heats a stream of water.In some embodiments, steam may also be generated through the use ofplant or factory waste heat. In some embodiments, the chloride salt,anhydrous or hydrated, is also heated.

In the case of Mg²⁺ and Ca²⁺, the reactions may be represented byequations 9 and 10, respectively:

MgCl₂+2H₂O→Mg(OH)₂+2HCl(g)ΔH=263 kJ/mole**  (9)

CaCl₂+2H₂O→Ca(OH)₂+2HCl(g)ΔH=284 kJ/mole**  (10)

**Measured at 100° C. The reactions are endothermic meaning energy,e.g., heat has to be applied to make these reactions occur. Such energymay be obtained from the waste-heat generated from one or more of theexothermic process steps disclosed herein. The above reactions may occuraccording to one of more of the following steps:

CaCl₂+(x+y+z)H₂O→Ca²⁺ .xH₂O+Cl⁻ .yH₂O+Cl⁻ .zH₂O  (11)

Ca⁺² .xH₂O+Cl⁻ .yH₂O+Cl⁻.zH₂O→[Ca²⁺.(x−1)(H₂O)OH⁻]⁺+Cl⁻.(yH₂O)+Cl⁻.(z−1)H₂O+H₃O⁺  (12)

[Ca²⁺.(x−1)(H₂O)OH⁻]⁺+Cl⁻.(yH₂O)+Cl⁻.(z−1)H₂O+H₃O⁺→[Ca²⁺.(x−1)(H₂O)OH⁻]⁺+Cl⁻.(yH₂O)+zH₂O+HCl(g)↑  (13)

[Ca²⁺.(x−1)(H₂O)OH⁻]⁺+Cl⁻.(yH₂O)→[Ca²⁺.(x−2)(H₂O)(OH⁻)₂]+Cl⁻.(y−1)H₂O+H₃O⁺  (14)

[Ca²⁺.(x−2)(H₂O)(OH⁻)₂]+Cl⁻.(y−1)H₂O+H₃O⁺→Ca(OH)₂↓+(x−2)H₂O+yH₂O+HCl↑(15)

The reaction enthalpy (ΔH) for CaCl₂+2 H₂O→Ca(OH)₂+2HCl(g) is 284kJ/mole at 100° C. In some variants, the salt MgCl₂.6H₂O, magnesiumhexahydrate, is used. Since water is incorporated into the molecularstructure of the salt, direct heating without any additional steam orwater may be used to initiate the decomposition. Typical reactionstemperatures for the following reactions are shown here:

From 95-110° C.:

MgCl₂.6H₂O→MgCl₂.4H₂O+2H₂O  (16)

MgCl₂.4H₂O→MgCl₂.2H₂O+2H₂O  (17)

From 135-180° C.:

MgCl₂.4H₂O→Mg(OH)Cl+HCl+3H₂O  (18)

MgCl₂.2H₂O→MgCl₂.H₂O+H₂O  (19)

From 185-230° C.:

MgCl₂.2H₂O→Mg(OH)Cl+HCl+H₂O  (20)

From >230° C.:

MgCl₂.H₂O→MgCl₂+H₂O  (21)

MgCl₂.H₂O→Mg(OH)Cl+HCl  (22)

Mg(OH)Cl→MgO+HCl  (23)

Referenced ΔH Temp. Reaction Temp. Range kJ/mole** Reaction MgCl₂•6H₂O →MgCl₂•4H₂O + 2 H₂O(g)  95° C.-110° C. 115.7 100° C. MgCl₂•4H₂O →MgCl₂•2H₂O + 2 H₂O(g)  95° C.-110° C. 134.4 100° C. MgCl₂•4H₂O →Mg(OH)Cl + HCl(g) + 3 135° C.-180° C. 275 160° C. H₂O(g) MgCl₂•2H₂O →MgCl₂•H₂O + H₂O(g) 135° C.-180° C. 70.1 160° C. MgCl₂•2H₂O → Mg(OH)Cl +HCl(g) + 185° C.-230° C. 141 210° C. H₂O(g) MgCl₂•H₂O → MgCl₂ +H₂O(g) >230° C. 76.6 240° C. MgCl₂•H₂O → Mg(OH)Cl + HCl(g) >230° C. 70.9240° C. Mg(OH)Cl → MgO + HCl(g) >230° C. 99.2 450° C. **ΔH values werecalculated at the temperature of reaction (column “Temp. Reaction”). Seethe chemical reference Kirk Othmer 4^(th) ed. Vol. 15 p. 343 1998 JohnWiley and Sons, which is incorporated herein by reference. See example1, below, providing results from a simulation that demonstrating theability to capture CO₂ from flue gas using an inexpensive raw material,CaCl₂, to form CaCO₃. See also Energy Requirements and Equilibrium inthe dehydration, hydrolysis and decomposition of Magnesium Chloride - K.K. Kelley, Bureau of Mines 1941 and Kinetic Analysis of ThermalDehydration and Hydrolysis of MgCl2•6H2O by DTA and TG - Y. Kirsh, S.Yariv and S. Shoval - Journal of Thermal Analysis, Vol. 32 (1987), bothof which are incorporated herein by reference in their entireties.

V. REACTION OF GROUP 2 HYDROXIDES AND CO₂ TO FORM GROUP 2 CARBONATES

In another aspect of the present disclosure, there are providedapparatuses and methods for the decarbonation of carbon dioxide sourcesusing Group 2 hydroxides, Group 2 oxides, and/or Group 2 hydroxidechlorides as CO₂ adsorbents. In some embodiments, CO₂ is absorbed intoan aqueous caustic mixture and/or solution where it reacts with thehydroxide and/or oxide salts to form carbonate and bicarbonate products.Sodium hydroxide, calcium hydroxide and magnesium hydroxide, in variousconcentrations, are known to readily absorb CO₂. Thus, in embodiments ofthe present invention, Group 2 hydroxides, Group 2 oxides (such as CaOand/or MgO) and/or other hydroxides and oxides, e.g., sodium hydroxidemay be used as the absorbing reagent.

For example, a Group 2 hydroxide, e.g., obtained from a Group 2chloride, may be used in an adsorption tower to react with and therebycapture CO₂ based on one or both of the following reactions:

Ca(OH)₂+CO₂→CaCO₃+H₂O  (24)

ΔH=−117.92 kJ/mol**

ΔG=−79.91 kJ/mol**

Mg(OH)₂+CO₂→MgCO₃+H₂O  (25)

ΔH=−58.85 kJ/mol**

ΔG=−16.57 kJ/mol**

** Calculated at STP.

In some embodiments of the present invention, most or nearly all of thecarbon dioxide is reacted in this manner. In some embodiments, thereaction may be driven to completion, for example, through the removalof water, whether through continuous or discontinous processes, and/orby means of the precipitation of bicarbonate, carbonate, or a mixture ofboth types of salts. See example 1, below, providing a simulationdemonstrating the ability to capture CO₂ from flue gas using aninexpensive raw material, Ca(CO)₂ derived from CaCl₂, to form CaCO₃.

In some embodiments, an initially formed Group 2 may undergo an saltexchange reaction with a second Group 2 hydroxide to transfer thecarbonate anion. For example:

CaCl₂+MgCO₃+→MgCl₂+CaCO₃  (25a)

These methods and devices can be further modified, optimized and scaledup using the principles and techniques of chemistry, chemicalengineering, and/or materials science as applied by a person skilled inthe art. Such principles and techniques are taught, for example, in U.S.Pat. No. 7,727,374, U.S. patent application Ser. No. 11/233,509, filedSep. 22, 2005, U.S. Provisional Patent Application No. 60/718,906, filedSep. 20, 2005; U.S. Provisional Patent Application No. 60/642,698, filedJan. 10, 2005; U.S. Provisional Patent Application No. 60/612,355, filedSep. 23, 2004, U.S. patent application Ser. No. 12/235,482, filed Sep.22, 2008, U.S. Provisional Application No. 60/973,948, filed Sep. 20,2007, U.S. Provisional Application No. 61/032,802, filed Feb. 29, 2008,U.S. Provisional Application No. 61/033,298, filed Mar. 3, 2008, U.S.Provisional Application No. 61/288,242, filed Jan. 20, 2010, U.S.Provisional Application No. 61/362,607, filed Jul. 8, 2010, andInternational Application No. PCT/US08/77122, filed Sep. 19, 2008. Theentire text of each of the above-referenced disclosures (including anyappendices) is specifically incorporated by reference herein.

VI. SILICATE MINERALS FOR THE SEQUESTRATION OF CARBON DIOXIDE

In aspects of the present invention there are provided methods ofsequestering carbon dioxide using silicate minerals. The silicateminerals make up one of the largest and most important classes ofrock-forming minerals, constituting approximately 90 percent of thecrust of the Earth. They are classified based on the structure of theirsilicate group. Silicate minerals all contain silicon and oxygen. Insome aspects of the present invention, Group 2 silicates may be used toaccomplish the energy efficient sequestration of carbon dioxide.

In some embodiments, compositions comprising Group 2 inosilicates may beused. Inosilicates, or chain silicates, have interlocking chains ofsilicate tetrahedra with either SiO₃, 1:3 ratio, for single chains orSi₄O₁₁, 4:11 ratio, for double chains.

In some embodiments, the methods disclosed herein use compositionscomprising Group 2 inosilicates from the pyroxene group. For example,enstatite (MgSiO₃) may be used.

In some embodiments, compositions comprising Group 2 inosilicates fromthe pyroxenoid group are used. For example, wollastonite (CaSiO₃) may beused. In some embodiments, compositions comprising mixtures of Group 2inosilicates may be employed, for example, mixtures of enstatite andwollastonite. In some embodiments, compositions comprising mixed-metalGroup 2 inosilicates may be used, for example, diopside (CaMgSi₂O₆).

Wollastonite usually occurs as a common constituent of a thermallymetamorphosed impure limestone. Typically wollastonite results from thefollowing reaction (equation 26) between calcite and silica with theloss of carbon dioxide:

CaCO₃+SiO₂→CaSiO₃+CO₂  (26)

In some embodiments, the present invention has the result of effectivelyreversing this natural process. Wollastonite may also be produced in adiffusion reaction in skarn. It develops when limestone within asandstone is metamorphosed by a dyke, which results in the formation ofwollastonite in the sandstone as a result of outward migration ofcalcium ions.

In some embodiments, the purity of the Group 2 inosilicate compositionsmay vary. For example, it is contemplated that the Group 2 inosilicatecompositions used in the disclosed processes may contain varying amountsof other compounds or minerals, including non-Group 2 metal ions. Forexample, wollastonite may itself contain small amounts of iron,magnesium, and manganese substituting for calcium.

In some embodiments, compositions comprising olivine and/or serpentinemay be used. CO₂ mineral sequestration processes utilizing theseminerals have been attempted. The techniques of Goldberg et al. (2001)are incorporated herein by reference.

The mineral olivine is a magnesium iron silicate with the formula(Mg,Fe)₂SiO₄. When in gem-quality, it is called peridot. Olivine occursin both mafic and ultramafic igneous rocks and as a primary mineral incertain metamorphic rocks. Mg-rich olivine is known to crystallize frommagma that is rich in magnesium and low in silica. Upon crystallization,the magna forms mafic rocks such as gabbro and basalt. Ultramafic rocks,such as peridotite and dunite, can be residues left after extraction ofmagmas and typically are more enriched in olivine after extraction ofpartial melts. Olivine and high pressure structural variants constituteover 50% of the Earth's upper mantle, and olivine is one of the Earth'smost common minerals by volume. The metamorphism of impure dolomite orother sedimentary rocks with high magnesium and low silica content alsoproduces Mg-rich olivine, or forsterite.

VII. GENERATION OF GROUP 2 CHLORIDES FROM GROUP 2 SILICATES

Group 2 silicates, e.g., CaSiO₃, MgSiO₃, and/or other silicatesdisclosed herein, may be reacted with hydrochloric acid, either as a gasor in the form of aqueous hydrochloric acid, to form the correspondingGroup 2 metal chlorides (CaCl₂ and/or MgCl₂), water and sand. In someembodiments the HCl produced in equation 1 is used to regenerate theMgCl₂ and/or CaCl₂ in equation 3. A process loop is thereby created.Table 1 below depicts some of the common calcium/magnesium containingsilicate minerals that may be used, either alone or in combination.Initial tests by reacting olivine and serpentine with HCl have beensuccessful. SiO₂ was observed to precipitate out and MgCl₂ and CaCl₂were collected.

TABLE 1 Calcium/Magnesium Minerals. Formula Formula Ratio Ratio Mineral(std. notation) (oxide notation) Group 2:SiO₂ Group 2:total Olivine(Mg,Fe)₂[SiO₄] (MgO,FeO)₂•SiO₂ 1:1 1:2 Serpentine Mg₆[OH]₈[Si₄O₁₀]6MgO•4SiO₂•4H₂O 3:2 undefined Sepiolite Mg₄[(OH)₂Si₆O₁₅]6H₂O3MgO•Mg(OH)₂•6SiO₂•6H₂O 2:3 undefined Enstatite Mg₂[Si₂O₆] 2MgO•2SiO₂1:1 undefined Diopside CaMg[Si₂O₆] CaO•MgO•2SiO₂ 1:1 undefined TremoliteCa₂Mg₅{[OH]Si₄O₁₁}₂ 2CaO•5MgO•8SiO₂H₂O 7:8 undefined Wollastonite CaSiO₃CaO•SiO₂ 1:1 undefined See “Handbook of Rocks, Minerals & Gemstones byWalter Schumann Published 1993, Houghton Mifflin Co., Boston, New York,which is incorporated herein by reference.

VIII. FURTHER EMBODIMENTS

In some embodiments, the conversion of carbon dioxide to mineralcarbonates may be defined by two salts. The first salt is one that maybe heated to decomposition until it becomes converted to a base(hydroxide and/or oxide) and emits an acid, for example, as a gas. Thissame base reacts with carbon dioxide to form a carbonate, bicarbonate orbasic carbonate salt.

For example, in some embodiments, the present disclosure providesprocesses that react one or more salts from Tables A-C below with waterto form a hydroxides, oxides, and/or a mixed hydroxide halides. Suchreactions are typically referred to as decompositions. In someembodiments, the water may be in the form of liquid, steam, and/or froma hydrate of the selected salt. The steam may come from a heat exchangerwhereby heat from an immensely combustible reaction, i.e. natural gasand oxygen or hydrogen and chlorine heats a stream of water. In someembodiments, steam may also be generated through the use of plant orfactory waste heat. In some embodiments, the halide salt, anhydrous orhydrated, is also heated.

TABLE A Decomposition Salts Li⁺ Na⁺ K⁺ Rb⁺ Cs⁺ F⁻ NC N 4747 N NC N 10906N 7490 N Cl⁻ 3876 N 19497 N 8295 N 13616 N 7785 N Br⁻ 3006 N 4336 N 9428N 13814 N 8196 N I⁻ 6110 N 6044 N 11859 N 9806 N 8196 N

TABLE B Decomposition Salts (cont.) Mg⁺² Ca⁺² Sr⁺² Ba⁺² F⁻ 4698 N 3433 N10346 N 6143 N Cl⁻  4500*  6W* 5847 2W 9855 6W 8098 2W Br⁻ 5010 6W 2743N 10346 6W 8114 2W I⁻ 2020 N 4960 N 9855 6W 10890 2W *Subsequent testshave proven the heat of reaction within 1.5-4% of the thermodynamicallyderived value using TGA (thermogravinometric analysis) of heated samplesand temperature ramp settings.

TABLE C Decomposition Salts (cont.) Mn⁺² Fe⁺² Co⁺² Ni⁺² Zn+² F⁻ 3318 N2101 N 5847 N 5847 N 3285 N Cl⁻ 5043 6W 3860 4W 3860 6W 4550 6W 8098 4WBr⁻ 5256 6W 11925 4W 9855 6W 5010 6W 4418 4W I⁻ 5043 6W 3055 4W 4123 6W5831 6W 4271 4W SO₄ ⁻² NC 4W 13485 4W 3351 4W 8985 6W 8344 7W

TABLE D Decomposition Salts (cont.) Ag⁺ La⁺³ F⁻ 2168 N 13255 7W Cl⁻ 5486N 7490 7W Br⁻ 6242 N 5029 7W I⁻ 6110 N 4813 7W SO₄ ⁻² 6159 N 10561 6WFor Tables A-D, the numerical data corresponds to the energy per amountof CO₂ captured in kWh/tonne, NC=did not converge, and NA=data notavailable.

This same carbonate, bicarbonate or basic carbonate of the first saltreacts with a second salt to do a carbonate/bicarbonate exchange, suchthat the anion of second salt combines with the cation of the first saltand the cation of the second salt combines with thecarbonate/bicarbonate ion of the first salt, which forms the finalcarbonate/bicarbonate.

In some cases the hydroxide derived from the first salt is reacted withcarbon dioxide and the second salt directly to form acarbonate/bicarbonate derived from (combined with the cation of) thesecond salt. In other cases the carbonate/bicarbonate/basic carbonatederived from (combined with the cation of) the first salt is removedfrom the reactor chamber and placed in a second chamber to react withthe second salt. FIG. 27 shows an embodiment of this 2-salt process.

This reaction may be beneficial when making a carbonate/bicarbonate whena salt of the second metal is desired, and this second metal is not ascapable of decomposing to form a CO₂ absorbing hydroxide, and if thecarbonate/bicarbonate compound of the second salt is insoluble, i.e. itprecipitates from solution. Below is a non-exhaustive list of examplesof such reactions that may be used either alone or in combination,including in combination with one or more either reactions discussedherein.

Examples for a Decomposition of a Salt-1

2NaI+H₂O→Na₂O+2HI and/or Na₂O+H₂O→2NaOH

MgCl₂.6H₂O→MgO+5H₂O+2HCl and/or MgO+H₂O→Mg(OH)₂

Examples of a Decarbonation

2NaOH+CO₂→Na₂CO₃+H₂O and/or Na₂CO₃+CO₂+H₂O2NaHCO₃

Mg(OH)₂+CO₂→MgCO₃+H₂O and/or Mg(OH)₂+2CO₂Mg(HCO₃)₂

Examples of a Carbonate exchange with a Salt-2:

Na₂CO₃+CaCl₂→CaCO₃↓+2NaCl

Na₂CO₃+2AgNO₃→Ag₂CO₃↓+2NaNO₃

Ca(OH)₂+Na₂CO₃→CaCO₃↓+2NaOH*

* In this instance the carbonate, Na₂CO₃ is Salt-2, and the saltdecomposed to form Ca(OH)₂, i.e. CaCl₂ is the Salt-1. This is thereverse of some of the previous examples in that the carbonate ionremains with Salt-1.

Known carbonate compounds include H₂CO₃, Li₂CO₃, Na₂CO₃, K₂CO₃, Rb₂CO₃,Cs₂CO₃, BeCO₃, MgCO₃, CaCO₃, MgCO₃, SrCO₃, BaCO₃, MnCO₃, FeCO₃, CoCO₃,CuCO₃, ZnCO₃, Ag₂CO₃, CdCO₃, Al₂(CO₃)₃, Tl₂CO₃, PbCO₃, and La₂(CO₃)₃.Group IA elements are known to be stable bicarbonates, e.g., LiHCO₃,NaHCO₃, RbHCO₃, and CsHCO₃. Group HA and some other elements can alsoform bicarbonates, but in some cases, they may only be stable insolution. Typically rock-forming elements are H, C, O, F, Na, Mg, Al,Si, P, S, Cl, K, Ca, Ti, Mg and Fe. Salts of these that can be thermallydecomposed into corresponding hydroxides by the least amount of energyper mole of CO₂ absorbing hydroxide may therefore be consideredpotential Salt-1 candidates.

Based on the energies calculated in Tables A-D, several salts have lowerenergies than MgCl₂.6H₂O. Table E below, summarizes these salts and thepercent penalty reduction through their use relative to MgCl₂.6H₂O.

TABLE E Section Lower Energy Alternative Salts Compound kw-hr/tonne %reduction MgCl₂•6H2O 4500  0% LiCl 3876 16% LiBr 3006 50% NaBr 4336  4%MgI₂ 2020 123%  CaF₂ 3433 31% CaBr₂ 2743 64% MnF₂ 3318 36% FeF₂ 2102114%  FeCl₂•4H₂O 3860 17% FeI₂•4H₂0 3055 47% CoCl₂•6H₂O 3860 17%CoI₂•6H₂O 4123  9% CoSO₄•4H₂O 3351 34% ZnF₂•2H₂O 3285 37% ZnBr₂•4H₂O4418  2% ZnI₂•4H₂O 4271  5% CdF₂ 3137 43% AgF 2168 108% 

The following salts specify a decomposition reaction through theirrespective available MSDS information.

TABLE F Compound Decomposition Energy Notes MgCl₂•6H₂O 4500 MnCl₂•4H₂O5043 only Mn⁺² forms a stable carbonate NaI•2H₂O 1023 too rare CoI₂•6H₂O4123 too rare FeCl₂•4H₂O 3860 May oxidize to ferric oxide, this will notform a stable carbonate LiBr 3006 too rare Mg(NO₃)₂•4H₂O 1606 leaves NoxCoSO₄•4H₂O 3351 somewhat rare leaves SO₃ CdCl₂•2.5H₂O not aval. toxicbyproducts Ca(NO₃)₂•4H₂O 2331 leaves NO₂ Compound References MgCl₂•6H₂OMnCl₂•4H₂O http://avogadro.chem.iastate.edu/MSDS/MnCl2.htm NaI₂•H₂Ohttp://www.chemicalbook.com/ProductMSDSDetailCB6170714_EN.htm CoI₂•6H₂Ohttp://www.espimetals.com/index.php/msds/527-cobalt-iodide FeCl₂•4H₂OLiBr http://www.chemcas.com/material/cas/archive/7550-35-8_v1.aspMg(NO₃)₂•4H₂O http://avogadro.chem.iastate.edu/MSDS/MgNO3-6H2O.htmCoSO₄•4H₂O http://www.chemicalbook.com/ProductMSDSDetailCB0323842_EN.htmCdCl₂-2.5H2Ohttp://www.espimetals.com/index.php/msds/460-cadmium-chlorideCa(NO₃)₂•4H2Ohttp://avogadro.chem.iastate.edu/MSDS/Ca%28NO3%292-4H2O.htm

IX. LIMESTONE GENERATION AND USES

In aspects of the present invention there are provided methods ofsequestering carbon dioxide in the form of limestone. Limestone is asedimentary rock composed largely of the mineral calcite (calciumcarbonate: CaCO₃). This mineral has many uses, some of which areidentified below.

Limestone in powder or pulverized form, as formed in some embodiments ofthe present invention, may be used as a soil conditioner (agriculturallime) to neutralize acidic soil conditions, thereby, for example,neutralizing the effects of acid rain in ecosystems. Upstreamapplications include using limestone as a reagent in desulfurizations.

Limestone is an important stone for masonry and architecture. One of itsadvantages is that it is relatively easy to cut into blocks or moreelaborate carving. It is also long-lasting and stands up well toexposure. Limestone is a key ingredient of quicklime, mortar, cement,and concrete.

Calcium carbonate is also used as an additive for paper, plastics,paint, tiles, and other materials as both white pigment and aninexpensive filler. Purified forms of calcium carbonate may be used intoothpaste and added to bread and cereals as a source of calcium. CaCO₃is also commonly used medicinally as an antacid.

Currently, the majority of calcium carbonate used in industry isextracted by mining or quarrying. By co-generating this mineral as partof carbon dioxide sequestration in some embodiments, this inventionprovides a non-extractive source of this important product.

X. MAGNESIUM CARBONATE GENERATION AND USES

In aspects of the present invention there are provided methods ofsequestering carbon dioxide in the form of magnesium carbonate.Magnesium carbonate, MgCO₃, is a white solid that occurs in nature as amineral. The most common magnesium carbonate forms are the anhydroussalt called magnesite (MgCO₃) and the di, tri, and pentahydrates knownas barringtonite (MgCO₃.2H₂O), nesquehonite (MgCO₃.3H₂O), andlansfordite (MgCO₃.5H₂O), respectively. Magnesium carbonate has avariety of uses; some of these are briefly discussed below.

Magnesium carbonate may be used to produce magnesium metal and basicrefractory bricks. MgCO₃ is also used in flooring, fireproofing, fireextinguishing compositions, cosmetics, dusting powder, and toothpaste.Other applications are as filler material, smoke suppressant inplastics, a reinforcing agent in neoprene rubber, a drying agent, alaxative, and for color retention in foods. In addition, high puritymagnesium carbonate is used as antacid and as an additive in table saltto keep it free flowing.

Currently magnesium carbonate is typically obtained by mining themineral magnesite. By co-generating this mineral as part of carbondioxide sequestration in some embodiments, this invention provides anon-extractive source of this important product.

XI. SILICON DIOXIDE GENERATION AND USES

In aspects of the present invention there are provided methods ofsequestering carbon dioxide that produce silicon dioxide as a byproduct.Silicon dioxide, also known as silica, is an oxide of silicon with achemical formula of SiO₂ and is known for its hardness. Silica is mostcommonly found in nature as sand or quartz, as well as in the cell wallsof diatoms. Silica is the most abundant mineral in the Earth's crust.This compound has many uses; some of these are briefly discussed below.

Silica is used primarily in the production of window glass, drinkingglasses and bottled beverages. The majority of optical fibers fortelecommunications are also made from silica. It is a primary rawmaterial for many whiteware ceramics such as earthenware, stoneware andporcelain, as well as industrial Portland cement.

Silica is a common additive in the production of foods, where it is usedprimarily as a flow agent in powdered foods, or to absorb water inhygroscopic applications. In hydrated form, silica is used in toothpasteas a hard abrasive to remove tooth plaque. Silica is the primarycomponent of diatomaceous earth which has many uses ranging fromfiltration to insect control. It is also the primary component of ricehusk ash which is used, for example, in filtration and cementmanufacturing.

Thin films of silica grown on silicon wafers via thermal oxidationmethods can be quite beneficial in microelectronics, where they act aselectric insulators with high chemical stability. In electricalapplications, it can protect the silicon, store charge, block current,and even act as a controlled pathway to limit current flow.

Silica is typically manufactured in several forms including glass,crystal, gel, aerogel, fumed silica, and colloidal silica. Byco-generating this mineral as part of carbon dioxide sequestration insome embodiments, this invention provides another source of thisimportant product.

XII. SEPARATION OF PRODUCTS

Separation processes may be employed to separate carbonate andbicarbonate products from the liquid solution and/or reaction mixture.By manipulating the basic concentration, temperature, pressure, reactorsize, fluid depth, and degree of carbonation, precipitates of one ormore carbonate and/or bicarbonate salts may be caused to occur.

Alternatively, carbonate/bicarbonate products may be separated fromsolution by the exchange of heat energy with incoming flue-gases.

The exit liquid streams, depending upon reactor design, may includewater, CaCO₃, MgCO₃, Ca(HCO₃)₂, Mg(HCO₃)₂, Ca(OH)₂, Ca(OH)₂, NaOH,NaHCO₃, Na₂CO₃, and other dissolved gases in various equilibria.Dissolved trace emission components such as H₂SO₄, HNO₃, and Hg may alsobe found. In one embodiment, removing/separating the water from thecarbonate product involves adding heat energy to evaporate water fromthe mixture, for example, using a reboiler. Alternatively, retaining apartial basic solution and subsequently heating the solution in aseparating chamber may be used to cause relatively pure carbonate saltsto precipitate into a holding tank and the remaining hydroxide salts torecirculate back to the reactor. In some embodiments, pure carbonate,pure bicarbonate, and mixtures of the two in equilibrium concentrationsand/or in a slurry or concentrated form may then be periodicallytransported to a truck/tank-car. In some embodiments, the liquid streamsmay be displaced to evaporation tanks/fields where the liquid, such aswater, may be carried off by evaporation.

The release of gaseous products includes a concern whether hydroxide oroxide salts will be released safely, i.e., emitting “basic rain.”Emission of such aerosolized caustic salts may be prevented in someembodiments by using a simple and inexpensive condenser/reflux unit.

In some embodiments, the carbonate salt may be precipitated usingmethods that are used separately or together with a water removalprocess. Various carbonate salt equilibria have characteristic rangeswhere, when the temperature is raised, a given carbonate salt, e.g.,CaCO₃ will naturally precipitate and collect, which makes it amenable tobe withdrawn as a slurry, with some fractional NaOH drawn off in theslurry.

XIII. RECOVERY OF WASTE-HEAT

Because certain embodiments of the present invention are employed in thecontext of large emission of CO₂ in the form of flue-gas or other hotgases from combustion processes, such as those which occur at a powerplant, there is ample opportunity to utilize this ‘waste’ heat, forexample, for the conversion of Group 2 chlorides salts into Group 2hydroxides. For instance, a typical incoming flue-gas temperature (afterelectro-static precipitation treatment, for instance) is approximately300° C. Heat exchangers can lower that flue-gas to a point less than300° C., while warming the water and/or Group 2 chloride salt tofacilitate this conversion.

Generally, since the flue-gas that is available at power-plant exits attemperatures between 100° C. (scrubbed typical), 300° C. (afterprecipitation processing), and 900° C. (precipitation entrance), orother such temperatures, considerable waste-heat processing can beextracted by cooling the incoming flue-gas through heat-exchange with apower-recovery cycle, for example an ammonia-water cycle (e.g., a“Kalina” cycle), a steam cycle, or any such cycle that accomplishes thesame thermodynamic means. Since some embodiments of the presentinvention rely upon DC power to accomplish the manufacture of thereagent/absorbent, the process can be directly powered, partially orwholly, by waste-heat recovery that is accomplished without the normaltransformer losses associated with converting that DC power to AC powerfor other uses. Further, through the use of waste-heat-to-work engines,significant efficiencies can be accomplished without an electricitygeneration step being employed at all. In some conditions, thesewaste-heat recovery energy quantities may be found to entirely powerembodiments of the present invention.

XIV. ALTERNATIVE PROCESSES

As noted above, some embodiments of the apparatuses and methods of thepresent disclosure produce a number of useful intermediates,by-products, and final products from the various reaction steps,including hydrogen chloride, Group 2 carbonate salts, Group 2 hydroxidesalts, etc. In some embodiments, some or all of these may be used in oneor more of the methods described below. In some embodiments, some or allof one of the starting materials or intermediates employed in one ormore of the steps described above are obtained using one or more of themethods outlined below.

A. Use of Chlorine for the Chlorination of Group 2 Silicates

In some embodiments the chlorine gas may be liquefied to hydrochloricacid that is then used to chlorinate Group 2 silicate minerals.Liquefaction of chlorine and subsequent use of the hydrochloric acid isparticularly attractive especially in situations where the chlorinemarket is saturated. Liquefaction of chlorine may be accomplishedaccording to equation 27:

Cl₂(g)+2H₂O(l)+hv(363 nm)→2HCl(l)+½O₂(g)  (27)

In some embodiments, the oxygen so produced may be returned to theair-inlet of the power plant itself, where it has been demonstratedthroughout the course of power-industry investigations that enrichedoxygen-inlet plants have (a) higher Carnot-efficiencies, (b) moreconcentrated CO₂ exit streams, (c) lower heat-exchange to warm inletair, and (d) other advantages over non-oxygen-enhanced plants. In someembodiments, the oxygen may be utilized in a hydrogen/oxygen fuel cell.In some embodiments, the oxygen may serve as part of the oxidant in aturbine designed for natural gas power generation, for example, using amixture of hydrogen and natural gas.

B. Use of Chlorine for the Chlorination of Group 2 Hydroxides

In some embodiments the chlorine gas may be reacted with a Group 2hydroxide salts to yield a mixture of a chloride and a hypochloritesalts (equation 28). For example, HCl may be sold as a product and theGroup 2 hydroxide salt may be used to remove excess chlorine.

Ca/Mg(OH)₂+Cl₂→½Ca/Mg(OCl)₂+½Ca/MgCl₂+H₂O  (28)

The Group 2 hypochlorites may then be decomposed using a cobalt ornickel catalyst to form oxygen and the corresponding chloride (equation29).

Ca/Mg(OCl)₂→Ca/MgCl₂+O₂  (29)

The calcium chloride and/or the magnesium chloride may then berecovered.

XV. REMOVAL OF OTHER POLLUTANTS FROM SOURCE

In addition to removing CO₂ from the source, in some embodiments of theinvention, the decarbonation conditions will also remove SO_(X) andNO_(X) and, to a lesser extent, mercury. In some embodiments of thepresent invention, the incidental scrubbing of NO_(X), SO_(X), andmercury compounds can assume greater economic importance; i.e., byemploying embodiments of the present invention, coals that contain largeamounts of these compounds can be combusted in the power plant with, insome embodiments, less resulting pollution than with higher-grade coalsprocessed without the benefit of the CO₂ absorption process. Suchprinciples and techniques are taught, for example, in U.S. Pat. No.7,727,374, U.S. patent application Ser. No. 11/233,509, filed Sep. 22,2005, U.S. Provisional Patent Application No. 60/718,906, filed Sep. 20,2005; U.S. Provisional Patent Application No. 60/642,698, filed Jan. 10,2005; U.S. Provisional Patent Application No. 60/612,355, filed Sep. 23,2004, U.S. patent application Ser. No. 12/235,482, filed Sep. 22, 2008,U.S. Provisional Application No. 60/973,948, filed Sep. 20, 2007, U.S.Provisional Application No. 61/032,802, filed Feb. 29, 2008, U.S.Provisional Application No. 61/033,298, filed Mar. 3, 2008, U.S.Provisional Application No. 61/288,242, filed Jan. 20, 2010, U.S.Provisional Application No. 61/362,607, filed Jul. 8, 2010, andInternational Application No. PCT/US08/77122, filed Sep. 19, 2008. Theentire text of each of the above-referenced disclosures (including anyappendices) is specifically incorporated by reference herein.

XVI. EXAMPLES

The following examples are included to demonstrate some embodiments ofthe invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the examples which follow representtechniques discovered by the inventor to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

Example 1 Process Simulation of Capture CO₂ from Flue Gas Using CaCl₂ toform CaCO₃

One embodiment of the present invention was simulated using Aspen Plusv. 7.1 software using known reaction enthalpies, reaction free energiesand defined parameters to determine mass and energy balances andsuitable conditions for capturing CO₂ from a flue gas stream utilizingCaCl₂ and heat to form CaCO₃ product. These results show that it ispossible to capture CO₂ from flue gas using inexpensive raw materials,CaCl₂ and water, to form CaCO₃.

Part of the defined parameters includes the process flow diagram shownin FIG. 5. Results from the simulation suggest that it is efficient torecirculate an MgCl₂ stream to react with H₂O and heat to form Mg(OH)₂.This Mg(OH)₂ then reacts with a saturated CaCl₂/H₂O solution and CO₂from the flue gas to form CaCO₃, which is filtered out of the stream.The resulting MgCl₂ formed is recycled to the first reactor to begin theprocess again. This process is not limited to any particular source forCaCl₂. For example, it may be obtained from reacting calcium silicatewith HCl to yield CaCl₂.

Constraints and parameters specified for this simulation include:

-   -   The reactions were run at 100% efficiencies with no losses. The        simulations can be modified when pilot runs determine the        reaction efficiencies.    -   Simulations did not account for impurities in the CaCl₂ feed        stock or in any make-up MgCl₂ required due to losses from the        system.

The results of this simulation indicate a preliminary net energyconsumption of approximately 130 mM Btu/hr. Tables 2a and 2b providemass and energy accounting for the various streams (the columns in thetable) of the simulated process. Each stream corresponds to the streamof FIG. 5.

The process consists of two primary reaction sections and one solidsfiltration section. The first reactor heats MgCl₂/water solution causingit to break down into a HCl/H₂O vapor stream and a liquid stream ofMg(OH)₂. The HCl/H₂O vapor stream is sent to the HCl absorber column.The Mg(OH)₂ solution is sent to reactor 2 for further processing. Thechemical reaction for this reactor can be represented by the followingequation:

MgCl₂+2H₂O→Mg(OH)₂+2HCl  (30)

A CaCl₂ solution and a flue gas stream are added to the MgCl₂ in reactor2. This reaction forms CaCO₃, MgCl₂ and water. The CaCO₃ precipitatesand is removed in a filter or decanter. The remaining MgCl₂ and waterare recycled to the first reactor. Additional water is added to completethe water balance required by the first reactor. The chemical reactionfor this reactor can be represented by the following equation:

Mg(OH)₂+CaCl₂+CO₂→CaCO₃(s)+MgCl₂+H₂O  (31)

The primary feeds to this process are CaCl₂, flue gas (CO₂) and water.MgCl₂ in the system is used, reformed and recycled. The only MgCl₂make-up required is to replace small amounts that leave the system withthe CaCO₃ product, and small amounts that leave with the HCl/waterproduct.

This process is a net energy user. There is cross heat exchange torecover the heat in high temperature streams to preheat the feedstreams. Significant heat recovery may be obtained by reacting theconcentrated HCl thus formed with silicate minerals.

TABLE 2a Mass and Energy Accounting for Simulation of Capture CO₂ fromFlue Gas Using CaCl₂ to form CaCO₃. Process Stream Names 1 2 3 BOTTOMSCaCl₂ CaCO₃ FG-IN H₂O H₂O—MgOH Temperature F. 485.8 151.6 250 95 77 95104 77 536 Pressure psia 15 15 15 15 15 15 15 15 15 Vapor Frac 0 0 0.0250 0 1 0 0 Mole Flow lbmol/hr 1594.401 7655.248 7653.691 3568.272 139.697139.502 611.154 2220.337 1594.401 Mass Flow lb/hr 53195.71 162514.8162514.8 115530.1 15504 13962.37 19206 40000 53195.71 Volume Flowgal/min 38.289 238.669 12389.12 114.43 14.159 30680.73 80.111 40.178Enthalpy MMBtu/hr −214.568 −918.028 −909.155 −574.405 −47.795 −27.903−273.013 −205.695 H₂O 1473.175 105624.1 105603 33281.39 750.535 400001473.172 H₂ Cl₂ HCl trace trace 0.001 trace trace CO₂ <0.001 0.091 0.0056158.236 CO O₂ 0.055 0.055 0.055 2116.894 N₂ 0.137 0.137 0.137 10180.34CaCl₂ 15504 Ca(OH)₂ CaCO₃ Mg(OH)₂ Mg(OH)Cl MgCl₂ MgCO₃ Ca(O)Cl₂ CaCl₂O₂Ca²⁺ 7.797 trace 7.797 Mg²⁺ 11114.84 14507.52 14506.86 11942.37 11115.59H⁺ <0.001 trace trace trace trace <0.001 CaOH⁺ <0.001 trace <0.001 MgOH⁺22.961 15.364 17.613 25.319 20.435 HClO MgCO₃—3W MgCl₂(s) MgCl₂—6W21433.25 MgCl₂—4W CaCl₂(s) CaCO₃(s) 13962.37 13962.37 MgCO₃(s) 0.174CaCl₂—6W 42.623 CaCl₂—4W CaCl₂—2W MgCl₂—2W MgCl₂—W Ca(OH)₂(s) Mg(OH)₂(s)8137.518 7.043 5.576 0.08 8139.306 ClO⁻ HCO₃ ⁻ 0.001 <0.001 0.119 Cl⁻32447.21 42352.6 42338.81 34877.24 32447.21 OH⁻ <0.001 0.001 0.001<0.001 <0.001 <0.001 CO₃ ²⁻ trace trace 0.001 H₂O 0.028 0.65 0.65 0.2880.039 1 0.028 H₂ Cl₂ HCl trace trace  3 PPB trace trace CO₂ trace 563PPB  40 PPB 0.321 CO O₂ 336 PPB 336 PPB 473 PPB 0.11 N₂ 844 PPB 844 PPB  1 PPM 0.53 CaCl₂ 1 Ca(OH)₂ CaCO₃ Mg(OH)₂ Mg(OH)Cl MgCl₂ MgCO₃ Ca(O)Cl₂CaCl₂O₂ Ca²⁺  48 PPM trace  67 PPM Mg²⁺ 0.209 0.089 0.089 0.103 0.209 H⁺  1 PPB trace trace trace trace 5 PPB CAOH⁺  1 PPB trace  1 PPB MgOH⁺432 PPM  95 PPM  108 PPM  219 PPM 384 PPM HClO MgCO₃—3W MgCl₂(s)MgCl₂—6W 0.186 MgCl₂—4W CaCl₂(s) CaCO₃(s) 0.121 1 MgCO₃(s)   1 PPMCaCl₂—6W  262 PPM CaCl₂—4W CaCl₂—2W MgCl₂—2W MgCl₂—W Ca(OH)₂(s)Mg(OH)₂(s) 0.153  43 PPM  34 PPM 691 PPB 0.153 ClO⁻ HCO₃ ⁻  5 PPB trace  1 PPM Cl⁻ 0.61 0.261 0.261 0.302 0.61 OH⁻ trace  6 PPB  6 PPB trace 2PPB trace CO₃ ²⁻ trace trace  12 PPB H₂O 81.774 5863.026 5861.8571847.398 41.661 2220.337 81.773 H₂ Cl₂ HCl trace trace <0.001 tracetrace CO₂ trace 0.002 <0.001 139.929 CO O₂ 0.002 0.002 0.002 66.155 N₂0.005 0.005 0.005 363.408 CaCl₂ 139.697 Ca(OH)₂ CaCO₃ Mg(OH)₂ Mg(OH)ClMgCl₂ MgCO₃ Ca(O)Cl₂ CaCl₂O₂ Ca²⁺ 0.195 trace 0.195 Mg²⁺ 457.328 596.922596.894 491.376 457.358 H⁺ <0.001 trace trace trace trace <0.001 CAOH⁺trace trace trace MgOH⁺ 0.556 0.372 0.426 0.613 0.495 HClO MgCO₃—3WMgCl₂(s) MgCl₂—6W 105.426 MgCl₂—4W CaCl₂(s) CaCO₃(s) 139.502 139.502MgCO₃(s) 0.002 CaCl₂—6W 0.195 CaCl₂—4W CaCl₂—2W MgCl₂—2W MgCl₂—WCa(OH)₂(s) Mg(OH)₂(s) 139.533 0.121 0.096 0.001 139.564 ClO⁻ HCO₃ ⁻<0.001 trace 0.002 Cl⁻ 915.211 1194.604 1194.215 983.753 915.211 OH⁻trace <0.001 <0.001 trace trace trace CO₃ ²⁻ trace trace <0.001 H₂O0.051 0.766 0.766 0.518 0.068 1 0.051 H₂ Cl₂ HCl trace trace  2 PPBtrace trace CO₂ trace 271 PPB  29 PPB 0.229 CO O₂ 223 PPB 223 PPB 478PPB 0.108 N₂ 640 PPB 640 PPB   1 PPM 0.595 CaCl₂ 1 Ca(OH)₂ CaCO₃ Mg(OH)₂Mg(OH)Cl MgCl₂ MgCO₃ Ca(O)Cl₂ CaCl₂O₂ Ca²⁺  25 PPM trace  55 PPM Mg²⁺0.287 0.078 0.078 0.138 0.287 H⁺  49 PPB trace trace trace 2 PPB 156PPB  CaOH⁺ trace trace trace MgOH⁺ 349 PPM  49 PPM  56 PPM  172 PPM 310PPM  HClO MgCO₃—3W MgCl₂(s) MgCl₂—6W 0.03 MgCl₂—4W CaCl₂(s) CaCO₃(s)0.039 1 MgCO₃(s) 269 PPB CaCl₂—6W  25 PPM CaCl₂—4W CaCl₂—2W MgCl₂—2WMgCl₂—W Ca(OH)₂(s) Mg(OH)₂(s) 0.088  16 PPM  12 PPM 383 PPB 0.088 ClO⁻HCO₃ ⁻  2 PPB trace 547 PPB Cl⁻ 0.574 0.156 0.156 0.276 0.574 OH⁻   1PPB  8 PPB  7 PPB trace 2 PPB 1 PPB CO₃ ²⁻ trace trace  6 PPB PH 5.3196.955 5.875 7.557 6.999 5.152

TABLE 2b Mass and Energy Accounting for Simulation of Capture CO₂ fromFlue Gas Using CaCl₂ to form CaCO₃. Process Stream Names H₂O—IN HCl—H₂OMg—CaCl₂ MgOH—O1 RETURN RX3-VENT Temperature F. 77 536 250 286.8 95 95Pressure psia 15 15 15 15 15 15 Vapor Frac 0 1 0.025 0.021 0 1 Mole Flow3383.073 5781.846 7655.866 3814.738 3427.371 433.305 lbmol/hr Mass Flowlb/hr 60947 109319.3 162515 93195.71 101567.8 12375.59 Volume Flow122.063 512251.6 12240.14 5364.891 104.123 21428.56 gal/min Enthalpy−415.984 −561.862 −909.177 −487.581 −502.044 −0.364 MMBtu/hr H₂O 6094799124.11 105634.7 41473.17 33262.52 59.861 H₂ Cl₂ HCl 10195.18 0.0870.009 trace trace CO₂ trace 18.689 CO O₂ 0.055 2116.839 N₂ 0.137 10180.2CaCl₂ Ca(OH)₂ CaCO₃ Mg(OH)₂ Mg(OH)Cl MgCl₂ MgCO₃ Ca(O)Cl₂ CaCl₂O₂ Ca²⁺7.797 Mg²⁺ 14519.48 11116.3 11938.09 H⁺ trace <0.001 trace trace CaOH⁺<0.001 MgOH⁺ 0.112 17.999 25.309 HClO MgCO₃—3W MgCl₂(s) MgCl₂—6W21468.81 MgCl₂—4W CaCl₂(s) CaCO₃(s) MgCO₃(s) 0.175 CaCl₂—6W CaCl₂—4WCaCl₂—2W MgCl₂—2W MgCl₂—W Ca(OH)₂(s) Mg(OH)₂(s) 8141.025 0.024 ClO⁻ HCO₃⁻ trace Cl⁻ 42360.62 32447.2 34864.84 OH⁻ <0.001 trace <0.001 <0.001 CO₃²⁻ trace Mass Frac H₂O 1 0.907 0.65 0.445 0.327 0.005 H₂ Cl₂ HCl 0.093534 PPB 92 PPB trace trace CO₂ trace 0.002 CO O₂ 538 PPB 0.171 N₂ 1 PPM0.823 CaCl₂ Ca(OH)₂ CaCO₃ Mg(OH)₂ Mg(OH)Cl MgCl₂ MgCO₃ Ca(O)Cl₂ CaCl₂O₂Ca²⁺ 77 PPM Mg²⁺ 0.089 0.119 0.118 H⁺ trace 2 PPB trace trace CaOH⁺ 1PPB MgOH⁺ 689 PPB 193 PPM 249 PPM HClO MgCO₃—3W MgCl₂(s) MgCl₂—6W 0.211MgCl₂—4W CaCl₂(s) CaCO₃(s) MgCO₃(s) 2 PPM CaCl₂—6W CaCl₂—4W CaCl₂—2WMgCl₂—2W MgCl₂—W Ca(OH)₂(s) Mg(OH)₂(s) 0.087 240 PPB ClO⁻ HCO₃ ⁻ traceCl⁻ 0.261 0.348 0.343 OH⁻ 2 PPB trace 2 PPB trace CO₃ ²⁻ trace H₂O3383.073 5502.224 5863.617 2302.111 1846.35 3.323 H₂ Cl₂ HCl 279.6220.002 <0.001 trace trace CO₂ trace 0.425 CO O₂ 0.002 66.154 N₂ 0.005363.404 CaCl₂ Ca(OH)₂ CaCO₃ Mg(OH)₂ Mg(OH)Cl MgCl₂ MgCO₃ Ca(O)Cl₂CaCl₂O₂ Ca²⁺ 0.195 Mg²⁺ 597.414 457.388 491.201 H⁺ trace <0.001 tracetrace CaOH⁺ trace MgOH⁺ 0.003 0.436 0.613 HClO MgCO₃—3W MgCl₂(s)MgCl₂—6W 105.601 MgCl₂—4W CaCl₂(s) CaCO₃(s) MgCO₃(s) 0.002 CaCl₂—6WCaCl₂—4W CaCl₂—2W MgCl₂—2W MgCl₂—W Ca(OH)₂(s) Mg(OH)₂(s) 139.593 <0.001ClO⁻ HCO₃ ⁻ trace Cl⁻ 1194.83 915.211 983.403 OH⁻ trace trace tracetrace CO₃ ²⁻ trace H₂O 1 0.952 0.766 0.603 0.539 0.008 H₂ Cl₂ HCl 0.048311 PPB 62 PPB trace trace CO₂ trace 980 PPM CO O₂ 498 PPB 0.153 N₂ 1PPM 0.839 CaCl₂ Ca(OH)₂ CaCO₃ Mg(OH)₂ Mg(OH)Cl MgCl₂ MgCO₃ Ca(O)Cl₂CaCl₂O₂ Ca²⁺ 57 PPM Mg²⁺ 0.078 0.12 0.143 H⁺ 2 PPB 43 PPB trace traceCaOH⁺ trace MgOH⁺ 354 PPB 114 PPM 179 PPM HClO MgCO₃—3W MgCl₂(s)MgCl₂—6W 0.031 MgCl₂—4W CaCl₂(s) CaCO₃(s) MgCO₃(s) 607 PPB CaCl₂—6WCaCl₂—4W CaCl₂—2W MgCl₂—2W MgCl₂—W Ca(OH)₂(s) Mg(OH)₂(s) 0.037 122 PPBClO⁻ HCO₃ ⁻ trace Cl⁻ 0.156 0.24 0.287 OH⁻ 2 PPB trace 2 PPB trace CO₃²⁻ trace PH 6.999 3.678 5.438 7.557

Example 2 (Case 1)—Process Simulation of Magnesium Ion Catalyzed CaptureCO₂ from Flue Gas Using CaCl₂ to form CaCO₃

Results from the simulation suggest that it is efficient to heat aMgCl₂.6H₂O stream in three separate dehydration reactions, each in itsown chamber, followed by a decomposition reaction, also in its ownchamber, to form Mg(OH)Cl and HCl, i.e. total of four chambers. TheMg(OH)Cl is reacted with H₂O to form MgCl₂ and Mg(OH)₂, which thenreacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas toform CaCO₃, which is filtered out of the stream. The resultingMgCl₂.6H₂O formed is recycled along with the earlier product to thefirst reactor to begin the process again.

This process is not limited to any particular source for CaCl₂. Forexample, it may be obtained from reacting calcium silicate with HCl toyield CaCl₂.

Constraints and parameters specified for this simulation include:

-   -   The reactions were run at 100% efficiencies with no losses. The        simulations can be modified when pilot runs determine the        reaction efficiencies.    -   Simulations did not account for impurities in the CaCl₂ feed        stock or in any make-up MgCl₂ required due to losses from the        system.    -   Part of the defined parameters include the process flow diagram        shown in FIG. 6.

The results of this simulation indicate a preliminary net energyconsumption of 5946 kwh/tonne CO₂. Table 3 provides mass and energyaccounting for the various streams of the simulated process. Each streamcorresponds to the stream of FIG. 6.

The process consists of two primary reactors and one solids filtrationsection. The first reactor heats MgCl₂.6H₂O causing it to break downinto a HCl/H₂O vapor stream and a solid stream of Mg(OH)Cl. The HCl/H₂Ovapor stream is sent to a heat exchanger to recover extra heat. TheMg(OH)₂ formed from the Mg(OH)Cl is sent to reactor 2 for furtherprocessing. Chemical reaction(s) occurring in this reactor include thefollowing:

MgCl₂.6H₂O+Δ→Mg(OH)Cl+5H₂O↑+HCl↑  (32)

2Mg(OH)Cl(aq)→Mg(OH)₂+MgCl₂  (33)

A CaCl₂ solution and a flue gas stream are added to the Mg(OH)₂ inreactor 2. This reaction forms CaCO₃, MgCl₂ and water. The CaCO₃precipitates and is removed in a filter or decanter. The remaining MgCl₂and water are recycled to the first reactor. Additional water is addedto complete the water balance required by the first reactor. Chemicalreaction(s) occurring in this reactor include the following:

Mg(OH)₂+CaCl₂+CO₂→CaCO₃↓(s)+MgCl₂+H₂O  (34)

The primary feeds to this process are CaCl₂, flue gas (CO₂) and water.MgCl₂ in the system is used, reformed and recycled. The only MgCl₂make-up required is to replace small amounts that leave the system withthe CaCO₃ product, and small amounts that leave with the HCl/waterproduct.

This process is a net energy user. The amount of energy is underinvestigation and optimization. There is cross heat exchange to recoverthe heat in high temperature streams to preheat the feed streams.

The steps for this process (Case 1) are summarized below:

CASE 1 3 STEP Dehydration then Decomposition Hexahydrate is dehydratedin 3 separate chambers. Step 1 hex to tetra, Step 2 tetra to di, Step 3di to mono. Monohydrate is decomposed into 80% Mg(OH)Cl 20% MgCl₂ in afourth chamber. CO₂ Absorbed 53333 MTPY CaCl₂ 134574 MTPY HCl Dry 88368MTPY CaCO₃ 105989 MTPY Hexahydrate recycled 597447 MTPY HEX TO TETRA(100° C.) 1757 kWh/tonne CO₂ TETRA TO DI (125 C. °) 2135 kWh/tonne CO₂DI TO MONO (160° C. & HCl PP) 1150 kWh/tonne CO₂ DECOMPOSITION (130° C.)1051 kWh/tonne CO₂ TO 80% Mg(OH)Cl 20% MgCl₂ YIELDS 90% HCl VAPOR 0.9 MWHeat Recovery 148 kWh/tonne CO₂ from 28% HCl vapor TOTAL 5946 kWh/tonneCO₂

TABLE 3a Mass and Energy Accounting for Case 1 Simulation. ProcessStream Names CaCl₂ CaCO₃ FLUEGAS H₂O H₂O-1 H₂O-2 HCl-PP HCl VAPORTemperature C. 25 95 104 25 100 125 160 130 Pressure psia 14.7 14.715.78 14.7 16.166 16.166 16.166 14.696 Mass VFrac 0 0 1 0 1 1 1 1 MassSFrac 1 1 0 0 0 0 0 0 Mass Flow tonne/year 134573.943 121369.558166332.6 290318.99 105883.496 105890.399 17179.526 97647.172 Volume Flowgal/min 30.929 22.514 76673.298 8099.644 82228.086 87740.919 10242.93548861.42 Enthalpy MW −30.599 −46.174 −17.479 −146.075 −44.628 −44.47−3.258 −10.757 Density lb/cuft 136.522 169.146 0.068 1.125 0.04 0.0380.053 0.063 H₂O 0 0 6499.971 290318.99 105883.496 105885.779 5681.2999278.695 H₂ 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 4.6211498.227 88368.477 CO₂ 0 0 53333.098 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 00 18333.252 0 0 0 0 0 N₂ 0 0 88166.278 0 0 0 0 0 CaCl₂ 134573.943 80.4990 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 CaCO₃ 0 121289.059 0 0 0 0 0 0 MgCO₃0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 00 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W0 0 0 0 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 MgO 0 00 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 0 0 H₂O 0 0 0.039 1 1 1 0.331 0.095 H₂0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 0 0.669 0.905 CO₂ 0 00.321 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 0 0 0.11 0 0 0 0 0 N₂ 0 0 0.53 0 00 0 0 CaCl₂ 1 0.001 0 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 CaCO₃ 0 0.999 00 0 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 00 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 00 0 0 0 MgCl₂*6W 0 0 0 0 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 00 0 0 0 0 MgO 0 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 0 0 H₂O 0 0 11.441511.008 186.372 186.376 10 16.332 H₂ 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0HCl 0 0 0 0 0 0.004 10 76.854 CO₂ 0 0 38.427 0 0 0 0 0 CO 0 0 0 0 0 0 00 O₂ 0 0 18.168 0 0 0 0 0 N₂ 0 0 99.8 0 0 0 0 0 CaCl₂ 38.45 0.023 0 0 00 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 CaCO₃ 0 38.427 0 0 0 0 0 0 MgCO₃ 0 0 0 0 00 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 00 0 MgCl₂*2W 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 00 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 00 MgHCO₃ ⁺ 0 0 0 0 0 0 0 0

TABLE 3b Mass and Energy Accounting for Case 1 Simulation. ProcessStream Names MgCl₂—2W MgCl₂—4W MgCl₂—6W RECYCIE1 RX2-VENT SLURRYSOLIDS-1 SOLIDS-2 VAPOR Temperature ° C. 125 100 104 95 95 95 160 130160 Pressure psia 16.166 16.166 14.696 14.7 14.7 14.7 22.044 14.69622.044 Mass VFrac 0 0 0 0 1 0 0 0 1 Mass SFrac 1 1 1 0.998 0 0.999 1 1 0Mass Flow tonne/year 385672.688 491563.087 597446.583 598447.468106499.178 719817.026 332737.843 235090.671 70114.371 Volume Flowgal/min 39.902 39.902 116.892 147.062 56469.408 167.321 39.902 43.47342506.729 Enthalpy MW −117.767 −175.272 −230.554 −231.312 0.241 −277.487−88.626 −71.431 −25.379 Density lb/cuft 303.274 386.542 160.371 127.6840.059 134.984 261.649 169.678 0.052 H₂O 0 0 0 1000 0 1000 0 0 58620.764H₂ 0 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 0 0 0 11493.607CO₂ 0 0 0 0 0.532 0 0 0 0 CO 0 0 0 0 0 0 0 0 0 O₂ 0 0 0 0.165 18333.0880.165 0 0 0 N₂ 0 0 0 0.72 88165.558 0.72 0 0 0 CaCl₂ 0 0 0 0 0 80.499 00 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 0 CaCO₃ 0 0 0 0 0 121289.059 0 0 0 MgCO₃ 0 00 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 49037.72 0MgCl₂*W 0 0 0 0 0 0 332737.843 0 0 MgCl₂*2W 385662.96 0 0 0 0 0 0 0 0MgCl₂*4W 0 491563.087 0 0 0 0 0 0 0 MgCl₂*6W 0 0 597446.583 597446.583 0597446.583 0 0 0 Mg(OH)Cl 9.728 0 0 0 0 0 0 186052.951 0 Mg(OH)₂ 0 0 0 00 0 0 0 0 MgO 0 0 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 0 0 0 H₂O 0 0 00.002 0 0.001 0 0 0.836 H₂ 0 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl 00 0 0 0 0 0 0 0.164 CO₂ 0 0 0 0 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 0 O₂ 0 0 00 0.172 0 0 0 0 N₂ 0 0 0 0 0.828 0 0 0 0 CaCl₂ 0 0 0 0 0 0 0 0 0 Ca(OH)₂0 0 0 0 0 0 0 0 0 CaCO₃ 0 0 0 0 0 0.168 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0 0Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0.209 0 MgCl₂*W 0 0 0 0 00 1 0 0 MgCl₂*2W 1 0 0 0 0 0 0 0 0 MgCl₂*4W 0 1 0 0 0 0 0 0 0 MgCl₂*6W 00 1 0.998 0 0.83 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 0.791 0 Mg(OH)₂ 0 0 0 0 00 0 0 0 MgO 0 0 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 0 0 0 H₂O 0 0 0 1.760 1.76 0 0 103.182 H₂ 0 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl 0 0 00 0 0 0 0 9.996 CO₂ 0 0 0 0 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 0 O₂ 0 0 0 018.168 0 0 0 0 N₂ 0 0 0 0.001 99.799 0.001 0 0 0 CaCl₂ 0 0 0 0 0 0.023 00 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 0 CaCO₃ 0 0 0 0 0 38.427 0 0 0 MgCO₃ 0 0 0 00 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 16.332 0MgCl₂*W 0 0 0 0 0 0 93.186 0 0 MgCl₂*2W 93.182 0 0 0 0 0 0 0 0 MgCl₂*4W0 93.186 0 0 0 0 0 0 0 MgCl₂*6W 0 0 93.186 93.186 0 93.186 0 0 0Mg(OH)Cl 0.004 0 0 0 0 0 0 76.854 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 0 MgO 0 0 00 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 0 0 0

Example 3 Process Simulation of Magnesium Ion Catalyzed Capture CO₂ fromFlue Gas Using CaCl₂ to form CaCO₃

Part of the defined parameters includes the process flow diagram shownin FIG. 7. Results from the simulation suggest that it is efficient toheat a MgCl₂.6H₂O stream to form Mg(OH)Cl in two separate dehydrationreactions, each in their own chambers followed by a decompositionreaction, also in its own chamber to form Mg(OH)Cl and HCl, i.e. a totalof three chambers. The Mg(OH)Cl is reacted with H₂O to form MgCl₂ andMg(OH)₂, which then reacts with a saturated CaCl₂/H₂O solution and CO₂from the flue gas to form CaCO₃, which is filtered out of the stream.The resulting MgCl₂.6H₂O formed is recycled to the first reactor tobegin the process again. This process is not limited to any particularsource for CaCl₂. For example, it may be obtained from reacting calciumsilicate with HCl to yield CaCl₂.

Constraints and parameters specified for this simulation include:

-   -   The reactions were run at 100% efficiencies with no losses. The        simulations can be modified when pilot runs determine the        reaction efficiencies.    -   Simulations did not account for impurities in the CaCl₂ feed        stock or in any make-up MgCl₂ required due to losses from the        system.

The results of this simulation indicate a preliminary net energyconsumption of 4862 kwh/tonne CO₂. Table 4 provides mass and energyaccounting for the various streams of the simulated process. Each streamcorresponds to the stream in FIG. 7.

The process consists of two primary reactors and one solids filtrationsection. The first reactor heats MgCl₂.6H₂O causing it to break downinto a HCl/H₂O vapor stream and a solid stream of Mg(OH)Cl. The HCl/H₂Ovapor stream is sent to a heat exchanger to recover extra heat. TheMg(OH)₂ formed from the Mg(OH)Cl is sent to reactor 2 for furtherprocessing. Chemical reaction(s) occurring in this reactor include thefollowing:

MgCl₂.6H₂O+Δ→Mg(OH)Cl+5H₂O↑HCl↑  (35)

2Mg(OH)Cl(aq)→Mg(OH)₂+MgCl₂  (36)

A CaCl₂ solution and a flue gas stream are added to the Mg(OH)₂ inreactor 2. This reaction forms CaCO₃, MgCl₂ and water. The CaCO₃precipitates and is removed in a filter or decanter. The remaining MgCl₂and water are recycled to the first reactor. Additional water is addedto complete the water balance required by the first reactor. Chemicalreaction(s) occurring in this reactor include the following:

Mg(OH)₂+CaCl₂+CO₂→CaCO₃↓(s)+MgCl₂+H₂O  (37)

The primary feeds to this process are CaCl₂, flue gas (CO₂) and water.MgCl₂ in the system is used, reformed and recycled. The only MgCl₂make-up required is to replace small amounts that leave the system withthe CaCO₃ product, and small amounts that leave with the HCl/waterproduct.

This process is a net energy user. The amount of energy is underinvestigation and optimization. There is cross heat exchange to recoverthe heat in high temperature streams to preheat the feed streams.

The steps for this process (Case 2) are summarized below:

CASE 2 2 STEP Dehydration then Decomposition Hexahydrate is dehydratedin 2 separate chambers. Step 1 hex to tetra, Step 2 tetra to di.Di-hydrate is decomposed into 100% Mg(OH)Cl. CO₂ Absorbed 53333 MTPYCaCl₂ 134574 MTPY HCl Dry 88368 MTPY CaCO₃ 105989 MTPY Hexahydraterecycled 492737 MTPY HEX TO TETRA (100° C.) 1445 kWh/tonne CO₂ TETRA TODI (125° C.) 1774 kWh/tonne CO₂ DI-HYDRATE DEHYDRATION & DECOMPOSITION1790 kWh/tonne CO₂ TO 100% Mg(OH)Cl (130° C.) YEILDS 66% HCl VAPOR NOCARRIER MgCl₂ = BETTER OVERALL EFFICIENCY NO USE OF HCl PP 0.9 HeatRecovery 148 kWh/tonne CO₂ from 28% HCl vapor TOTAL 4862 kWh/tonne CO₂

TABLE 4a Mass and Energy Accounting for Case 2 Simulation. ProcessStream Names 5 7 8 CaCl₂ CaCO₃ Temperature ° C. 98 114.1 101 25 95Pressure psia 14.696 14.696 14.696 14.7 14.7 Mass VFrac 0 0 1 0 0 MassSFrac 1 1 0 1 1 Mass Flow 492736.693 405410.587 306683.742 134573.943121369.558 tonne/year Volume Flow 96.405 32.909 224394.519 30.929 22.514gal/min Enthalpy MW −190.292 −144.291 −98.931 −30.599 −46.174 Densitylb/cuft 160.371 386.542 0.043 136.522 169.146 H₂O 0 0 218315.265 0 0 H₂0 0 0 0 0 Cl₂ 0 0 0 0 0 HCl 0 0 88368.477 0 0 CO₂ 0 0 0 0 0 CO 0 0 0 0 0O₂ 0 0 0 0 0 N₂ 0 0 0 0 0 CaCl₂ 0 0 0 134573.943 80.499 Ca(OH)₂ 0 0 0 00 CaCO₃ 0 0 0 0 121289.059 MgCO₃ 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 MgCl₂ 0 00 0 0 MgCl₂*W 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 405410.587 0 0 0MgCl₂*6W 492736.693 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 00 0 0 MgHCO₃ ⁺ 0 0 0 0 0 H₂O 0 0 0.712 0 0 H₂ 0 0 0 0 0 Cl₂ 0 0 0 0 0HCl 0 0 0.288 0 0 CO₂ 0 0 0 0 0 CO 0 0 0 0 0 O₂ 0 0 0 0 0 N₂ 0 0 0 0 0CaCl₂ 0 0 0 1 0.001 Ca(OH)₂ 0 0 0 0 0 CaCO₃ 0 0 0 0 0.999 MgCO₃ 0 0 0 00 Ca(O)Cl₂ 0 0 0 0 0 MgCl₂ 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 MgCl₂*2W 0 0 0 00 MgCl₂*4W 0 1 0 0 0 MgCl₂*6W 1 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 00 0 MgO 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 H₂O 0 0 384.27 0 0 H₂ 0 0 0 0 0 Cl₂0 0 0 0 0 HCl 0 0 76.854 0 0 CO₂ 0 0 0 0 0 CO 0 0 0 0 0 O₂ 0 0 0 0 0 N₂0 0 0 0 0 CaCl₂ 0 0 0 38.45 0.023 Ca(OH)₂ 0 0 0 0 0 CaCO₃ 0 0 0 0 38.427MgCO₃ 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 MgCl₂ 0 0 0 0 0 MgCl₂*W 0 0 0 0 0MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 76.854 0 0 0 MgCl₂*6W 76.854 0 0 0 0Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0Process Stream Names FLUEGAS H₂O H₂O-1 H₂O-2 HCl Vapor Temperature ° C.40 25 100 125 130 Pressure psia 15.78 14.7 14.696 22.044 14.696 MassVFrac 1 0 1 1 1 Mass SFrac 0 0 0 0 0 Mass Flow 166332.6 234646.8287326.106 87329.947 132027.689 tonne/year Volume Flow 63660.018 6546.4474598.258 53065.241 80593.954 gal/min Enthalpy MW −17.821 −118.063−36.806 −36.675 −25.187 Density lb/cuft 0.082 1.125 0.037 0.052 0.051H₂O 6499.971 234646.82 87326.106 87326.106 43663.053 H₂ 0 0 0 0 0 Cl₂ 00 0 0 0 HCl 0 0 0 3.841 88364.636 CO₂ 53333.098 0 0 0 0 CO 0 0 0 0 0 O₂18333.252 0 0 0 0 N₂ 88166.278 0 0 0 0 CaCl₂ 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0CaCO₃ 0 0 0 0 0 MgCO₃ 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 MgCl₂ 0 0 0 0 0MgCl₂*W 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 MgCl₂*6W 0 0 0 00 Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0H₂O 0.039 1 1 1 0.331 H₂ 0 0 0 0 0 Cl₂ 0 0 0 0 0 HCl 0 0 0 0 0.669 CO₂0.321 0 0 0 0 CO 0 0 0 0 0 O₂ 0.11 0 0 0 0 N₂ 0.53 0 0 0 0 CaCl₂ 0 0 0 00 Ca(OH)₂ 0 0 0 0 0 CaCO₃ 0 0 0 0 0 MgCO₃ 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0MgCl₂ 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0MgCl₂*6W 0 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 0 0 0 0MgHCO₃ ⁺ 0 0 0 0 0 H₂O 11.441 413.016 153.708 153.708 76.854 H₂ 0 0 0 00 Cl₂ 0 0 0 0 0 HCl 0 0 0 0.003 76.851 CO₂ 38.427 0 0 0 0 CO 0 0 0 0 0O₂ 18.168 0 0 0 0 N₂ 99.8 0 0 0 0 CaCl₂ 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0CaCO₃ 0 0 0 0 0 MgCO₃ 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 MgCl₂ 0 0 0 0 0MgCl₂*W 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 MgCl₂*6W 0 0 0 00 Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0

TABLE 4b Mass and Energy Accounting for Case 2 Simulation. ProcessStream Names LIQUID MgCl₂—4W MgCl₂—6W RECYCLE1 RX2-VENT SLURRY SOLIDS-1SOLIDS-2 VAPOR Temperature ° C. 94.9 100 75 95 95 95 125 130 118.1Pressure psia 14.696 14.696 14.696 14.7 14.7 14.7 22.044 14.696 14.696Mass VFrac 0.979 0 0 0 1 0 0 0 1 Mass SFrac 0 1 1 0.998 0 0.998 1 1 0Mass Flow tonne/ 306683.742 405410.587 492736.693 493737.578 106499.178615107.136 318080.64 186052.951 306683.742 year Volume Flow gal/215496.035 32.909 96.405 126.575 56469.408 146.834 32.909 32.909234621.606 min Enthalpy MW −99.487 −144.553 −190.849 −190.859 0.241−237.034 −97.128 −61.083 −98.668 Density lb/cuft 0.045 386.542 160.371122.394 0.059 131.442 303.277 177.393 0.041 H₂O 218315.265 0 0 1000 01000 0 0 218315.265 H₂ 0 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl88368.477 0 0 0 0 0 0 0 88368.477 CO₂ 0 0 0 0 0.532 0 0 0 0 CO 0 0 0 0 00 0 0 0 O₂ 0 0 0 0.165 18333.088 0.165 0 0 0 N₂ 0 0 0 0.72 88165.5580.72 0 0 0 CaCl₂ 0 0 0 0 0 80.499 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 0 CaCO₃0 0 0 0 0 121289.059 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 00 0 0 MgCl₂ 0 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 00 0 318077.568 0 0 MgCl₂*4W 0 405410.587 0 0 0 0 0 0 0 MgCl₂*6W 0 0492736.693 492736.693 0 492736.693 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0186052.951 0 Mg(OH)₂ 0 0 0 0 0 0 3.072 0 0 MgO 0 0 0 0 0 0 0 0 0 MgHCO₃⁺ 0 0 0 0 0 0 0 0 0 Mass Frac H₂O 0.712 0 0 0.002 0 0.002 0 0 0.712 H₂ 00 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl 0.288 0 0 0 0 0 0 0 0.288 CO₂0 0 0 0 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 0 O₂ 0 0 0 0 0.172 0 0 0 0 N₂ 0 0 00 0.828 0 0 0 0 CaCl₂ 0 0 0 0 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 0 CaCO₃0 0 0 0 0 0.197 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0MgCl₂ 0 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 10 0 MgCl₂*4W 0 1 0 0 0 0 0 0 0 MgCl₂*6W 0 0 1 0.998 0 0.801 0 0 0Mg(OH)Cl 0 0 0 0 0 0 0 1 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 00 MgHCO₃ ⁺ 0 0 0 0 0 0 0 0 0 H₂O 384.27 0 0 1.76 0 1.76 0 0 384.27 H₂ 00 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl 76.854 0 0 0 0 0 0 0 76.854CO₂ 0 0 0 0 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 0 O₂ 0 0 0 0 18.168 0 0 0 0 N₂0 0 0 0.001 99.799 0.001 0 0 0 CaCl₂ 0 0 0 0 0 0.023 0 0 0 Ca(OH)₂ 0 0 00 0 0 0 0 0 CaCO₃ 0 0 0 0 0 38.427 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0 0Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 00 0 MgCl₂*2W 0 0 0 0 0 0 76.852 0 0 MgCl₂*4W 0 76.854 0 0 0 0 0 0 0MgCl₂*6W 0 0 76.854 76.854 0 76.854 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 76.8540 Mg(OH)₂ 0 0 0 0 0 0 0.002 0 0 MgO 0 0 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 00 0 0 0

Example 4—Process Simulation of Magnesium Ion Catalyzed Capture CO₂ fromFlue Gas Using CaCl₂ to Form CaCO₃

Part of the defined parameters include the process flow diagram shown inFIG. 8. Results from the simulation suggest that it is efficient to heata MgCl₂.6H₂O stream to form MgO in a single chamber. The MgO is reactedwith H₂O to form Mg(OH)₂, which then reacts with a saturated CaCl₂/H₂Osolution and CO₂ from the flue gas to form CaCO₃, which is filtered outof the stream. The resulting MgCl₂.6H₂O formed is recycled to the firstreactor to begin the process again. This process is not limited to anyparticular source for CaCl₂. For example, it may be obtained fromreacting calcium silicate with HCl to yield CaCl₂.

Constraints and parameters specified for this simulation include:

-   -   The reactions were run at 100% efficiencies with no losses. The        simulations can be modified when pilot runs determine the        reaction efficiencies.    -   Simulations did not account for impurities in the CaCl₂ feed        stock or in any make-up MgCl₂ required due to losses from the        system.

The results of this simulation indicate a preliminary net energyconsumption of 3285 kwh/tonne CO₂. Table 5 provides mass and energyaccounting for the various streams of the simulated process. Each streamcorresponds to the stream of FIG. 8.

The process consists of two primary reactors and one solids filtrationsection. The first reactor heats MgCl₂.6H₂O causing it to break downinto a HCl/H₂O vapor stream and a solid stream of MgO. The HCl/H₂O vaporstream is sent to a heat exchanger to recover extra heat. The Mg(OH)₂formed from the MgO is sent to reactor 2 for further processing.Chemical reaction(s) occurring in this reactor include the following:

MgCl₂.6H₂O+Δ→MgO+5H₂O↑+2HCl↑  (38)

MgO+H₂O→Mg(OH)₂  (39)

A CaCl₂ solution and a flue gas stream are added to the Mg(OH)₂ inreactor 2. This reaction forms CaCO₃, MgCl₂ and water. The CaCO₃precipitates and is removed in a filter or decanter. The remaining MgCl₂and water are recycled to the first reactor. Additional water is addedto complete the water balance required by the first reactor. Chemicalreaction(s) occurring in this reactor include the following:

Mg(OH)₂+CaCl₂+CO₂→CaCO₃↓(s)+MgCl₂+H₂O  (40)

The primary feeds to this process are CaCl₂, flue gas (CO₂) and water.MgCl₂ in the system is used, reformed and recycled. The only MgCl₂make-up required is to replace small amounts that leave the system withthe CaCO₃ product, and small amounts that leave with the HCl/waterproduct.

This process is a net energy user. The amount of energy is underinvestigation and optimization. There is cross heat exchange to recoverthe heat in high temperature streams to preheat the feed streams.

The steps for this process (Case 3) are summarized below:

CASE 3 Combined Dehydration/Decomposition to MgO Hexahydrate isdehydrated and decomposed simultaneously at 450 C. Reactor yeilds 100%MgO. CO₂ Absorbed 53333 MTPY CaCl₂ 134574 MTPY HCl Dry 88368 MTPY CaCO₃105989 MTPY Hexahydrate recycled 246368 MTPY HEXAHYDRATE DEHYDRATION &DECOMPOSITION 3778 kWh/tonne CO2 TO 100% MgO (450° C.) YIELDS 44.7% HClVAPOR RECYCLES HALF AS MUCH HEXAHYDRATE BUT NEEDS HIGH QUALITY HEAT HeatRecovery 493 kWh/tonne CO2 from 45% HCl vapor TOTAL 3285 kWh/tonne CO2

TABLE 5a Mass and Energy Accounting for Case 3 Simulation. ProcessStream Names CaCl₂ CaCO₃ FLUE GAS H₂O HCl VAP MgCl₂ MgCl₂—6W Temperature° C. 25 95 104 25 120 353.8 104 Pressure psia 14.7 14.7 15.78 14.714.696 14.7 14.7 Mass VFrac 0 0 1 0 1 0 0 Mass SFrac 1 1 0 0 0 1 1 MassFlow tonne/year 134573.943 121369.558 166332.6 125489.188 197526.11246368.347 246368.347 Volume Flow gal/min 30.929 22.514 76673.2983501.038 137543.974 48.203 48.203 Enthalpy MW −30.599 −46.174 −17.479−63.14 −52.762 −92.049 −95.073 Density lb/cuft 136.522 169.146 0.0681.125 0.045 160.371 160.371 H₂O 0 0 6499.971 125489.188 109157.633 0 0H₂ 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 HCl 0 0 0 0 88368.477 0 0 CO₂ 0 053333.098 0 0 0 0 CO 0 0 0 0 0 0 0 O₂ 0 0 18333.252 0 0 0 0 N₂ 0 088166.278 0 0 0 0 CaCl₂ 134573.943 80.499 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 00 CaCO₃ 0 121289.059 0 0 0 0 0 MgCO₃ 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 00 MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0MgCl₂*4W 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0 246368.347 246368.347 Mg(OH)Cl0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 H₂O 0 0 0.039 10.553 0 0 H₂ 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 HCl 0 0 0 0 0.447 0 0 CO₂ 00 0.321 0 0 0 0 CO 0 0 0 0 0 0 0 O₂ 0 0 0.11 0 0 0 0 N₂ 0 0 0.53 0 0 0 0CaCl₂ 1 0.001 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 CaCO₃ 0 0.999 0 0 0 0 0MgCO₃ 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 00 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 MgCl₂*6W 0 0 00 0 1 1 Mg(OH)Cl 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0H₂O 0 0 11.441 220.881 192.135 0 0 H₂ 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0HCl 0 0 0 0 76.854 0 0 CO₂ 0 0 38.427 0 0 0 0 CO 0 0 0 0 0 0 0 O₂ 0 018.168 0 0 0 0 N₂ 0 0 99.8 0 0 0 0 CaCl₂ 38.45 0.023 0 0 0 0 0 Ca(OH)₂ 00 0 0 0 0 0 CaCO₃ 0 38.427 0 0 0 0 0 MgCO₃ 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 00 0 0 0 MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0MgCl₂*4W 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0 38.427 38.427 Mg(OH)Cl 0 0 0 00 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0

TABLE 5b Mass and Energy Accounting for Case 3 Simulation. ProcessStream Names Mg(OH)Cl1 Mg(OH)Cl2 RECYCLE1 RECYCLE2 RECYCLE3 RX2-VENTSLURRY VAPOR VENT Temperature ° C. 450 100 95 140 140 95 95 450 140Pressure psia 14.696 14.696 14.7 14.7 14.7 14.7 14.7 14.696 14.7 MassVFrac 0 0 0 0.004 0 1 0 1 1 Mass SFrac 1 1 0.996 0.996 1 0 0.997 0 0Mass Flow tonne/year 48842.237 48842.237 247369.231 247369.231246368.347 106499.178 368738.79 197526.11 1000.885 Volume Flow gal/min6.851 6.851 78.372 994.232 48.203 56469.408 98.632 252994.849 946.03Enthalpy MW −22.38 −23 −95.676 −95.057 −94.638 0.241 −141.851 −49.738−0.419 Density lb/cuft 223.695 223.695 99.036 7.807 160.371 0.059117.304 0.024 0.033 H₂O 0 0 1000 1000 0 0 1000 109157.633 1000 H₂ 0 0 00 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 0 0 88368.477 0 CO₂ 0 00 0 0 0.532 0 0 0 CO 0 0 0 0 0 0 0 0 0 O₂ 0 0 0.165 0.165 0 18333.0880.165 0 0.165 N₂ 0 0 0.72 0.72 0 88165.558 0.72 0 0.72 CaCl₂ 0 0 0 0 0 080.499 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 0 CaCO₃ 0 0 0 0 0 0 121289.059 0 0MgCO₃ 0 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 00 MgCl₂*W 0 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 00 0 0 0 0 MgCl₂*6W 0 0 246368.347 246368.347 246368.347 0 246368.347 0 0Mg(OH)Cl 0 0 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 0 MgO 48842.23748842.237 0 0 0 0 0 0 0 H₂O 0 0 0.004 0.004 0 0 0.003 0.553 0.999 H₂ 0 00 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 0 0 0.447 0 CO₂ 0 0 00 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 0 O₂ 0 0 0 0 0 0.172 0 0 0 N₂ 0 0 0 0 00.828 0 0 0.001 CaCl₂ 0 0 0 0 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 0 CaCO₃0 0 0 0 0 0 0.329 0 0 MgCO₃ 0 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0MgCl₂ 0 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 00 0 MgCl₂*4W 0 0 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0.996 0.996 1 0 0.668 0 0Mg(OH)Cl 0 0 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 0 MgO 1 1 0 0 0 0 0 00 H₂O 0 0 1.76 1.76 0 0 1.76 192.135 1.76 H₂ 0 0 0 0 0 0 0 0 0 Cl₂ 0 0 00 0 0 0 0 0 HCl 0 0 0 0 0 0 0 76.854 0 CO₂ 0 0 0 0 0 0 0 0 0 CO 0 0 0 00 0 0 0 0 O₂ 0 0 0 0 0 18.168 0 0 0 N₂ 0 0 0.001 0.001 0 99.799 0.001 00.001 CaCl₂ 0 0 0 0 0 0 0.023 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 0 CaCO₃ 0 0 00 0 0 38.427 0 0 MgCO₃ 0 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 0MgCl₂ 0 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 00 0 MgCl₂*4W 0 0 0 0 0 0 0 0 0 MgCl₂*6W 0 0 38.427 38.427 38.427 038.427 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 0 MgO38.427 38.427 0 0 0 0 0 0 0

Example 5 Process Simulation of Magnesium Ion Catalyzed Capture CO₂ fromFlue Gas Using CaCl₂ to form CaCO₃

Part of the defined parameters include the process flow diagram shown inFIG. 9. Results from the simulation suggest that it is efficient to heata MgCl₂.6H₂O stream to form Mg(OH)Cl in a single chamber. The Mg(OH)Clis reacted with H₂O to form MgCl₂ and Mg(OH)₂, which then reacts with asaturated CaCl₂/H₂O solution and CO₂ from the flue gas to form CaCO₃,which is filtered out of the stream. The resulting MgCl₂.6H₂O formed isrecycled to the first reactor to begin the process again. This processis not limited to any particular source for CaCl₂. For example, it maybe obtained from reacting calcium silicate with HCl to yield CaCl₂.

Constraints and parameters specified for this simulation include:

-   -   The reactions were run at 100% efficiencies with no losses. The        simulations can be modified when pilot runs determine the        reaction efficiencies.    -   Simulations did not account for impurities in the CaCl₂ feed        stock or in any make-up MgCl₂ required due to losses from the        system.

The results of this simulation indicate a preliminary net energyconsumption of 4681 kwh/tonne CO₂. Table 6 provides mass and energyaccounting for the various streams of the simulated process. Each streamcorresponds to the stream of FIG. 9.

The process consists of two primary reactors and one solids filtrationsection. The first reactor heats MgCl₂.6H₂O causing it to break downinto a HCl/H₂O vapor stream and a solid stream of Mg(OH)Cl. The HCl/H₂Ovapor stream is sent to a heat exchanger to recover extra heat. TheMg(OH)₂ formed from the Mg(OH)Cl is sent to reactor 2 for furtherprocessing. Chemical reaction(s) occurring in this reactor include thefollowing:

MgCl₂.6H₂O+Δ→Mg(OH)Cl+5H₂O↑+HCl↑  (41)

2Mg(OH)Cl(aq)→Mg(OH)₂+MgCl₂  (42)

A CaCl₂ solution and a flue gas stream are added to the Mg(OH)₂ inreactor 2. This reaction forms CaCO₃, MgCl₂ and water. The CaCO₃precipitates and is removed in a filter or decanter. The remaining MgCl₂and water are recycled to the first reactor. Additional water is addedto complete the water balance required by the first reactor. Chemicalreaction(s) occurring in this reactor include the following:

Mg(OH)₂+CaCl₂+CO₂→CaCO₃↓(s)+MgCl₂+H₂O  (43)

The primary feeds to this process are CaCl₂, flue gas (CO₂) and water.MgCl₂ in the system is used, reformed and recycled. The only MgCl₂make-up required is to replace small amounts that leave the system withthe CaCO₃ product, and small amounts that leave with the HCl/waterproduct.

This process is a net energy user. The amount of energy is underinvestigation and optimization. There is cross heat exchange to recoverthe heat in high temperature streams to preheat the feed streams.

The steps for this process (Case 4) are summarized below:

CASE 4 Combined Dehydration/Decomposition to Mg(OH)Cl Hexahydrate isdehydrated and decomposed simultaneously at 250° C. Reactor yields 100%Mg(OH)Cl. CO₂ Absorbed 53333 MTPY CaCl₂ 134574 MTPY HCl Dry 88368 MTPYCaCO₃ 105989 MTPY Hexahydrate recycled 492737 MTPY DEHYDRATION &DECOMPOSITION 5043 kWh/tonne CO2 TO 100% Mg(OH)Cl (250° C.) YEILDS 28.8%HCl VAPOR 2.2 MW Heat Recovery 361 kWh/tonne CO2 from 28% HCl vaporTOTAL 4681 kWh/tonne CO2

TABLE 6a Mass and Energy Accounting for Case 4 Simulation. ProcessStream Names CaCl₂ CaCO₃ FLUEGAS H₂O HCIVAP MgCl₂ MgCl₂—6W Mg(OH)Cl1Temperature ° C. 25 95 104 25 120 188 104 250 Pressure psia 14.7 14.715.78 14.7 14.696 14.7 14.7 14.696 Mass VFrac 0 0 1 0 1 0 0 0 Mass SFrac1 1 0 0 0 1 1 1 Mass Flow tonne/year 134573.943 121369.558 166332.6234646.82 306683.742 492736.693 492736.693 186052.951 Volume Flowgal/min 30.929 22.514 76673.298 6546.44 235789.67 96.405 96.405 32.909Enthalpy MW −30.599 −46.174 −17.479 −118.063 −98.638 −188.114 −190.147−60.661 Density lb/cuft 136.522 169.146 0.068 1.125 0.041 160.371160.371 177.393 H₂O 0 0 6499.971 234646.82 218315.265 0 0 0 H₂ 0 0 0 0 00 0 0 Cl₂ 0 0 0 0 0 0 0 0 HCl 0 0 0 0 88368.477 0 0 0 CO₂ 0 0 53333.0980 0 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 0 0 18333.252 0 0 0 0 0 N₂ 0 0 88166.2780 0 0 0 0 CaCl₂ 134573.943 80.499 0 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0CaCO₃ 0 121289.059 0 0 0 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 00 0 0 MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 00 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0 492736.693 492736.693 0Mg(OH)Cl 0 0 0 0 0 0 0 186052.951 Mg(OH)₂ 0 0 0 0 0 0 0 0 MgO 0 0 0 0 00 0 0 H₂O 0 0 0.039 1 0.712 0 0 0 H₂ 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0HCl 0 0 0 0 0.288 0 0 0 CO₂ 0 0 0.321 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 00 0.11 0 0 0 0 0 N₂ 0 0 0.53 0 0 0 0 0 CaCl₂ 1 0.001 0 0 0 0 0 0 Ca(OH)₂0 0 0 0 0 0 0 0 CaCO₃ 0 0.999 0 0 0 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0 Ca(O)Cl₂0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 MgCl₂*2W 00 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0 1 1 0 Mg(OH)Cl0 0 0 0 0 0 0 1 Mg(OH)₂ 0 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 0 H₂O 0 011.441 413.016 384.27 0 0 0 H₂ 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 HCl 00 0 0 76.854 0 0 0 CO₂ 0 0 38.427 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 0 018.168 0 0 0 0 0 N₂ 0 0 99.8 0 0 0 0 0 CaCl₂ 38.45 0.023 0 0 0 0 0 0Ca(OH)₂ 0 0 0 0 0 0 0 0 CaCO₃ 0 38.427 0 0 0 0 0 0 MgCO₃ 0 0 0 0 0 0 0 0Ca(O)Cl₂ 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0MgCl₂*2W 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 076.854 76.854 0 Mg(OH)Cl 0 0 0 0 0 0 0 76.854 Mg(OH)₂ 0 0 0 0 0 0 0 0MgO 0 0 0 0 0 0 0 0

TABLE 6b Mass and Energy Accounting for Case 4 Simulation. ProcessStream Names Mg(OH)Cl₂ RECYCLE1 RECYCLE2 RECYCLE3 RX2-VENT SLURRY VAPORVENT Temperature ° C. 100 95 113.8 113.8 95 95 250 113.8 Pressure psia14.696 14.7 14.7 14.7 14.7 14.7 14.696 14.7 Mass VFrac 0 0 0.002 0 1 0 11 Mass SFrac 1 0.998 0.998 1 0 0.998 0 0 Mass Flow tonne/year 186052.95493737.58 493737.58 492736.69 106499.18 615107.14 306683.74 1000.89Volume Flow gal/min 32.909 126.575 982.405 96.405 56469.408 146.834313756.5 886 Enthalpy MW −61.189 −190.859 −190.331 −189.91 0.241−237.034 −96.605 −0.421 Density lb/cuft 177.393 122.394 15.769 160.3710.059 131.442 0.031 0.035 H₂O 0 1000 1000 0 0 1000 218315.27 1000 H₂ 0 00 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 0 88368.477 0 CO₂ 0 0 0 00.532 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 0 0.165 0.165 0 18333.088 0.165 00.165 N₂ 0 0.72 0.72 0 88165.558 0.72 0 0.72 CaCl₂ 0 0 0 0 0 80.499 0 0Ca(OH)₂ 0 0 0 0 0 0 0 0 CaCO₃ 0 0 0 0 0 121289.06 0 0 MgCO₃ 0 0 0 0 0 00 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 00 MgCl₂*2W 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W 0 492736.69492736.69 492736.69 0 492736.69 0 0 Mg(OH)Cl 186052.95 0 0 0 0 0 0 0Mg(OH)₂ 0 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 0 H₂O 0 0.002 0.002 0 0 0.0020.712 0.999 H₂ 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 0 0.2880 CO₂ 0 0 0 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 0 0 0 0 0.172 0 0 0 N₂ 0 0 00 0.828 0 0 0.001 CaCl₂ 0 0 0 0 0 0 0 0 Ca(OH)₂ 0 0 0 0 0 0 0 0 CaCO₃ 00 0 0 0 0.197 0 0 MgCO₃ 0 0 0 0 0 0 0 0 Ca(O)Cl₂ 0 0 0 0 0 0 0 0 MgCl₂ 00 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0 0 MgCl₂*4W0 0 0 0 0 0 0 0 MgCl₂*6W 0 0.998 0.998 1 0 0.801 0 0 Mg(OH)Cl 1 0 0 0 00 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 0 H₂O 0 1.76 1.76 0 01.76 384.27 1.76 H₂ 0 0 0 0 0 0 0 0 Cl₂ 0 0 0 0 0 0 0 0 HCl 0 0 0 0 0 076.854 0 CO₂ 0 0 0 0 0 0 0 0 CO 0 0 0 0 0 0 0 0 O₂ 0 0 0 0 18.168 0 0 0N₂ 0 0.001 0.001 0 99.799 0.001 0 0.001 CaCl₂ 0 0 0 0 0 0.023 0 0Ca(OH)₂ 0 0 0 0 0 0 0 0 CaCO₃ 0 0 0 0 0 38.427 0 0 MgCO₃ 0 0 0 0 0 0 0 0Ca(O)Cl₂ 0 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0MgCl₂*2W 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W 0 76.85476.854 76.854 0 76.854 0 0 Mg(OH)Cl 76.854 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 00 0 0 0 MgO 0 0 0 0 0 0 0 0

Example 6 Road Salt Boiler: Decomposition of MgCl₂.6H₂O

FIG. 10 shows a graph of the mass percentage of a heated sample ofMgCl₂.6H₂O. The sample's initial mass was approximately 70 mg and set at100%. During the experiment, the sample's mass was measured while it wasbeing thermally decomposed. The temperature was quickly ramped up to150° C., and then slowly increased by 0.5° C. per minute. Atapproximately 220° C., the weight became constant, consistent with theformation of Mg(OH)Cl. The absence of further weight decrease indicatedthat almost all the water has been removed. Two different detaileddecompositional mass analyses are shown in FIGS. 28 and 29, with thetheoretical plateaus of different final materials shown. FIG. 30confirms that MgO can be made by higher temperatures (here, 500° C.)than those which produce Mg(OH)Cl.

Example 7 Dissolution of Mg(OH)Cl in H₂O

A sample of Mg(OH)Cl, produced by the heated decomposition ofMgCl₂.6H₂O, was dissolved in water and stirred for a period of time.Afterwards, the remaining precipitate was dried, collected and analyzed.By the formula of decomposition, the amount of Mg(OH)₂ could be comparedto the expected amount and analyzed. The chemical reaction can berepresented as follows:

2Mg(OH)Cl(aq)→Mg(OH)₂+MgCl₂  (44)

The solubility data for Mg(OH)₂ and MgCl₂ is as follows:

-   -   MgCl₂ 52.8 gm in 100 gm. H₂O (very soluble)    -   Mg(OH)₂ 0.0009 gm in 100 gm. H₂O (virtually insoluble)

Theoretical weight of recovered Mg(OH)₂:

Given weight of sample: 3.0136 gm.

-   -   MW Mg(OH)Cl 76.764    -   MW Mg(OH)₂ 58.32    -   Moles Mg(OH)₂ formed per mole Mg(OH)Cl=½

Expected amount of Mg(OH)₂

-   -   2 Mg(OH)Cl (aq) Mg(OH)₂+MgCl₂    -   3.016 gm*(MW Mg(OH)₂÷(MW Mg(OH)Cl*½=1.1447 gm

Precipitate collected=1.1245 gm

% of theoretical collected=(1.1447±1.1245)*100=98.24%

Analytical data:

Next the sample of Mg(OH)₂ was sent for analysis, XRD(X-ray-diffraction) and EDS. Results are shown in FIG. 11. The top rowof peaks is that of the sample, the spikes in the middle row are thesignature of Mg(OH)₂ while the spikes at the bottom are those of MgO.Thus verifying that the recovered precipitate from the dissolution ofMg(OH)Cl has a signal resembling that of Mg(OH)₂.

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.9472 1.014 96.88 96.02 +/−0.23 Si—K 0.0073 2.737 1.74 1.99 +/−0.17Cl—K 0.0127 1.570 1.38 2.00 +/−0.16 Total 100.00 100.00 Note: Results donot include elements with Z < 11 (Na).The EDS analysis reveals that very little chlorine [Cl] was incorporatedinto the precipitate. Note, this analysis cannot detect oxygen orhydrogen.

Example 8 Decarbonation Bubbler Experiment: Production of CaCO₃ byreacting CO₂ with Mg(OH)₂ {or Mg(OH)Cl} and CaCl₂

Approximately 20 grams of Mg(OH)₂ was placed in a bubble column with twoliters of water and CO₂ was bubbled though it for x minutes period oftime. Afterwards some of the liquid was collected to which a solution ofCaCl₂ was added. A precipitate immediately formed and was sent throughthe XRD and EDS. The chemical reaction can be represented as follows:

Mg(OH)₂+CO₂+CaCl₂→CaCO₃↓+H₂O  (45)

The XRD analysis (FIG. 12) coincides with the CaCO₃ signature.

EDS

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.0070 2.211 2.52 1.55 +/−0.10 Al—K 0.0013 1.750 0.33 0.22 +/−0.04 Si—K0.0006 1.382 0.12 0.09 +/−0.03 Cl—K 0.0033 1.027 0.38 0.34 +/−0.03 Ca—K0.9731 1.005 96.64 97.80 +/−0.30 Total 100.00 100.00 Note: Results donot include elements with Z < 11 (Na).The EDS analysis indicates almost pure CaCO₃ with only a 1.55% by weightmagnesium impurity and almost no Chlorine from the CaCl₂.

The same test was performed, except that Mg(OH)Cl from the decompositionof MgCl₂.6H₂O was used instead of Mg(OH)₂. Although Mg(OH)Cl has halfthe hydroxide [OH⁻], as Mg(OH)₂ it is expected to absorb CO₂ and formprecipitated CaCO₃ (PCC).

The XRD analysis (FIG. 13) coincides with the CaCO₃ signature.

EDS

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.0041 2.224 1.48 0.90 +/−0.09 S—K 0.0011 1.071 0.14 0.11 +/−0.04 Ca—K0.9874 1.003 98.38 98.98 +/−0.34 Total 100.00 100.00 Chi-sqd = 5.83Livetime = 300.0 Sec. Standardless Analysis PROZA Correction Acc. Volt.= 20 kV Take-off Angle = 35.00 deg Number of Iterations = 3 Note:Results do not include elements with Z < 11 (Na). Again the resultsindicate almost pure CaCO₃, almost no Mg or Cl compounds.

Example 9A Rock Melter Experiment: Reaction of Olivine and Serpentinewith HCl

Samples of olivine (Mg,Fe)₂SiO₄ and serpentine Mg₃Si₂O₅(OH)₄ werecrushed and reacted with 6.1 molar HCl over a period of approximately 72hours. Two sets of tests were run, the first at room temperature and thesecond at 70° C. These minerals have variable formulae and often containiron. After the samples were filtered, the resulting filtrand andfiltrate were dried in an oven overnight. The samples then went throughXRD and EDS analysis. The filtrates should have MgCl₂ present and thefiltrand should be primarily SiO₂.

Olivine Filtrate Reacted with HCl at Room Temperature

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.1960 1.451 37.06 28.45 +/−0.18 Si—K 0.0103 1.512 1.75 1.56 +/−0.11Cl—K 0.5643 1.169 58.89 65.94 +/−0.31 Fe—K 0.0350 1.161 2.30 4.06+/−0.22 Total 100.00 100.00Olivine Filtrate Reacted with HCl at 70° C.

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.1172 1.684 27.39 19.74 +/−0.12 Si—K 0.0101 1.459 1.77 1.48 +/−0.07Cl—K 0.5864 1.142 63.70 66.94 +/−0.24 Fe—K 0.0990 1.144 6.84 11.33+/−0.21 Ni—K 0.0045 1.128 0.29 0.51 +/−0.09 Total 100.00 100.00 Note:Results do not include elements with Z < 11 (Na).Serpentine Filtrate Reacted with HCl at Room Temperature

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.1674 1.466 32.47 24.53 +/−0.15 Al—K 0.0025 1.863 0.55 0.46 +/−0.06Si—K 0.0033 1.456 0.55 0.48 +/−0.04 Cl—K 0.6203 1.141 64.22 70.77+/−0.27 Ca—K 0.0016 1.334 0.17 0.21 +/−0.05 Cr—K 0.0026 1.200 0.19 0.31+/−0.07 Mn—K 0.0011 1.200 0.08 0.14 +/−0.08 Fe—K 0.0226 1.160 1.51 2.62+/−0.10 Ni—K 0.0042 1.128 0.26 0.48 +/−0.10 Total 100.00 100.00 Note:Results do not include elements with Z < 11 (Na).Serpentine Filtrate Reacted with HCl at 70° C.

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.1759 1.455 33.67 25.59 +/−0.14 Al—K 0.0017 1.886 0.39 0.33 +/−0.06Si—K 0.0087 1.468 1.46 1.28 +/−0.04 Cl—K 0.6014 1.152 62.46 69.27+/−0.25 Cr—K 0.0016 1.199 0.12 0.19 +/−0.06 Fe—K 0.0268 1.161 1.78 3.11+/−0.17 Ni—K 0.0020 1.130 0.12 0.22 +/−0.08 Total 100.00 100.00 Note:Results do not include elements with Z < 11 (Na). Note: Results do notinclude elements with Z < 11 (Na).

The filtrate clearly for both minerals serpentine and olivine at ambientconditions and 70° C. all illustrate the presence of MgCl₂, and a smallamount of FeCl₂ in the case of olivine.

Olivine Filtrand Reacted with HCl at Room Temperature

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.2239 1.431 37.68 32.04 +/−0.14 Si—K 0.3269 1.622 53.96 53.02 +/−0.19Cl—K 0.0140 1.658 1.87 2.32 +/−0.06 Cr—K 0.0090 1.160 0.58 1.05 +/−0.08Mn—K 0.0013 1.195 0.08 0.16 +/−0.09 Fe—K 0.0933 1.167 5.57 10.89 +/−0.26Ni—K 0.0045 1.160 0.25 0.52 +/−0.11 Total 100.00 100.00 Note: Results donot include elements with Z < 11 (Na).Olivine Filtrand Reacted with HCl at 70° C.

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.2249 1.461 38.87 32.86 +/−0.16 Si—K 0.3030 1.649 51.12 49.94 +/−0.21Cl—K 0.0223 1.638 2.96 3.65 +/−0.14 Ca—K 0.0033 1.220 0.29 0.41 +/−0.05Cr—K 0.0066 1.158 0.42 0.76 +/−0.08 Mn—K 0.0023 1.193 0.15 0.28 +/−0.10Fe—K 0.0937 1.163 5.61 10.89 +/−0.29 Ni—K 0.0074 1.158 0.42 0.86 +/−0.13Cu—K 0.0029 1.211 0.16 0.35 +/−0.16 Total 100.00 100.00 Note: Results donot include elements with Z < 11 (Na).

Given that the formula for olivine is (Mg,Fe)₂SiO₄, and this is amagnesium rich olivine. The raw compound has a Mg:Si ratio of 2:1.However the filtrand, that which does not pass through the filter has a(Mg+Fe:Si) ratio of (37+5.5:52) or 0.817:1. (Atom % on the chart),evidently more than 50% of the magnesium passed through the filter.

Serpentine Filtrand Reacted with HCl at Room Temperature

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.1930 1.595 37.32 30.78 +/−0.15 Si—K 0.2965 1.670 51.94 49.50 +/−0.20Cl—K 0.0065 1.633 0.88 1.06 +/−0.06 Cr—K 0.0056 1.130 0.36 0.63 +/−0.08Fe—K 0.1532 1.155 9.33 17.69 +/−0.31 Ni—K 0.0029 1.159 0.17 0.34 +/−0.12Total 100.00 100.00 Note: Results do not include elements with Z < 11(Na).Serpentine Filtrand Reacted with HCl at 70° C.

Element k-ratio ZAF (calc.) Wt % (1-Sigma) Atom % Element Wt % Err. Mg—K0.1812 1.536 33.53 27.83 +/−0.13 Si—K 0.3401 1.593 56.49 54.18 +/−0.18Cl—K 0.0106 1.651 1.45 1.75 +/−0.11 Cr—K 0.0037 1.142 0.24 0.43 +/−0.07Mn—K 0.0009 1.188 0.05 0.10 +/−0.08 Fe—K 0.1324 1.159 8.05 15.35 +/−0.26Ni—K 0.0032 1.160 0.18 0.37 +/−0.11 Total 100.00 100.00 Note: Results donot include elements with Z < 11 (Na).

Given that the formula of serpentine is (Mg,Fe)₃Si₂O₅(OH)₄ the initial1.5:1 ratio of (Mg+Fe) to Si has been whittled down to(37+9.3:56.5)=0.898:1.

Example 9B Temperature/Pressure Simulation for Decomposition ofMgC12.6(H₂O)

Pressure and temperature was varied, as shown below (Table 7) and inFIG. 14, to determine the effect this has on the equilibrium of thedecomposition of MgCl₂.6(H₂O). Inputs are:

-   -   1) MgCl₂.6H₂O    -   2) CaCl₂    -   3) The temperature of the hot stream leaving the heat exchanger        (HX) labeled Mg(OH)Cl (see FIGS. 7-8).    -   4) Percentage of Solids separated in decanter.    -   5) Water needed labeled H₂O    -   6) Flue Gas.

TABLE 7 VARY 1 VARY 2 REACTOR1 REACTOR1 PARAM PARAM TEMP PRES INPUTMg(OH)Cl MgO Q ° C. PSIA MOL/SEC MOL/SEC MOL/SEC MW kWh/tonne CO2 400 551.08399 25.31399 25.77001 23.63765 3883 410 5 38.427 0 38.427 19.856143261 420 5 38.427 0 38.427 19.87482 3264 430 5 38.427 0 38.427 19.893543268 440 5 38.427 0 38.427 19.9123 3271 450 5 38.427 0 38.427 19.931113274 400 7 76.854 76.854 0 31.37484 5153 410 7 53.24627 29.6385423.60773 24.31186 3993 420 7 38.427 0 38.427 19.87482 3264 430 7 38.4270 38.427 19.89354 3268 440 7 38.427 0 38.427 19.9123 3271 450 7 38.427 038.427 19.93111 3274 400 9 76.854 76.854 0 31.37484 5153 410 9 72.8511568.84829 4.002853 30.20646 4961 420 9 50.2148 23.5756 26.6392 23.424113847 430 9 38.427 0 38.427 19.89354 3268 440 9 38.427 0 38.427 19.91233271 450 9 38.427 0 38.427 19.93111 3274 400 11 76.854 76.854 0 31.374845153 410 11 76.854 76.854 0 31.41 5159 420 11 64.78938 52.72476 12.0646227.81251 4568 430 11 44.67748 12.50096 32.17652 21.77822 3577 440 1138.427 0 38.427 19.9123 3271 450 11 38.427 0 38.427 19.93111 3274 400 1376.854 76.854 0 31.37484 5153 410 13 76.854 76.854 0 31.41 5159 420 1376.854 76.854 0 31.44515 5165 430 13 55.59535 34.3367 21.25865 25.070264118 440 13 38.427 0 38.427 19.9123 3271 450 13 38.427 0 38.427 19.931113274 400 15 76.854 76.854 0 31.37484 5153 410 15 76.854 76.854 0 31.415159 420 15 76.854 76.854 0 31.44515 5165 430 15 66.51322 56.1724410.34078 28.36229 4659 440 15 46.41875 15.98351 30.43525 22.32544 3667450 15 38.427 0 38.427 19.93111 3274 200 5 127 76.854 0 47.51946 7805210 5 85 76.854 0 33.34109 5476 220 5 77 76.854 0 30.74184 5049 230 5 7776.854 0 30.77702 5055 240 5 77 76.854 0 30.8122 5061 250 5 77 76.854 030.84739 5067 200 7 184 76.854 0 66.57309 10935 210 7 125 76.854 046.75184 7679 220 7 85 76.854 0 33.32609 5474 230 7 77 76.854 0 30.7775055 240 7 77 76.854 0 30.81218 5061 250 7 77 76.854 0 30.84737 5067 2009 297 76.854 0 89.51079 14702 210 9 165 76.854 0 60.16258 9882 220 9 11376.854 0 42.92123 7050 230 9 78 76.854 0 31.04401 5099 240 9 77 76.854 030.81217 5061 250 9 77 76.854 0 30.84735 5067 200 11 473 76.854 0136.5784 22433 210 11 205 76.854 0 73.57332 12084 220 11 142 76.854 052.51638 8626 230 11 98 76.854 0 38.01558 6244 240 11 77 76.854 030.81216 5061 250 11 77 76.854 0 30.84734 5067 200 13 684 76.854 0192.9858 31698 210 13 303 76.854 0 91.43505 15018 220 13 170 76.854 062.11152 10202 230 13 119 76.854 0 44.98715 7389 240 13 83.3323 76.854 033.00459 5421 250 13 76.854 76.854 0 30.84733 5067 200 15 930.528776.854 0 258.7607 42502 210 15 422.9236 76.854 0 123.7223 20322 220 15198.7291 76.854 0 71.70666 11778 230 15 139.6567 76.854 0 51.95871 8534240 15 98.51739 76.854 0 38.14363 6265 250 15 76.854 76.854 0 30.847335067

Examples 10-21

The following remaining examples are concerned with obtaining thenecessary heat to perform the decomposition reaction using waste heatemissions from either coal or natural gas power plants. In order toobtain the necessary heat from coal flue gas emissions, the heat sourcemay be located prior to the baghouse where the temperature ranges from320-480° C. in lieu of the air pre-heater. See Reference: pages 11-15 of“The structural design of air and gas ducts for power stations andindustrial Boiler Applications,” Publisher: American Society of CivilEngineers (August 1995), which is incorporated by reference herein inits entirety. Open cycle natural gas plants have much higher exhausttemperatures of 600° C. See Reference: pages 11-15 of “The structuraldesign of air and gas ducts for power stations and industrial BoilerApplications,” Publisher: American Society of Civil Engineers (August1995), which is incorporated by reference herein in its entirety.Additionally, the decomposition reaction of MgCl₂.6H₂O may also run intwo different modes, complete decomposition to MgO or a partialdecomposition to Mg(OH)Cl. The partial decomposition to Mg(OH)Clrequires in some embodiments a temperature greater than 180° C. whereasthe total decomposition to MgO requires in some embodiments atemperature of 440° C. or greater.

Additionally the incoming feed to the process can be represented as acontinuum between 100% Calcium Silicate (CaSiO₃) and 100% MagnesiumSilicate (MgSiO₃) with Diopside (MgCa(SiO₃)₂) (or a mixture of CaSiO₃and MgSiO₃ in a 1:1 molar ratio) representing an intermediate 50% case.For each of these cases the resulting output will range in someembodiments from calcium carbonate (CaCO₃) to magnesium carbonate(MgCO₃) with Dolomite CaMg(CO₃)₂ representing the intermediate case. Theprocess using 100% calcium silicate is the Ca—Mg process used in all ofthe previously modeled embodiments. It is also important to note thatthe 100% magnesium silicate process uses no calcium compounds; whereasthe 100% calcium silicate incoming feed process does use magnesiumcompounds, but in a recycle loop, only makeup magnesium compounds arerequired.

Further details regarding the Ca—Mg, Mg only, Diopside processes, forexample, using complete and partial decomposition of hydrated MgCl₂ toMgO and Mg(OH)Cl, respectively, are depicted below.

I) Ca—Mg Process

Overall reaction CaSiO₃+CO₂→CaCO₃+SiO₂

-   -   a) Full decomposition (“the CaSiO₃—MgO process”):        -   1) MgCl₂.6H₂O+Δ→MgO+5H₂O↑+2HCl↑            -   A thermal decomposition reaction.        -   2) 2HCl(aq)+CaSiO₃→CaCl₂(aq)+SiO₂↓+H₂O            -   A rock melting reaction.            -   Note 5 H₂O will be present per 2 moles of HCl during the                reaction.        -   3) MgO+CaCl₂(aq)+CO₂→CaCO₃↓, +MgCl₂(aq)            -   Some versions of this equation use Mg(OH)₂ which is                formed from MgO and H₂O.        -   4) MgCl₂(aq)+6H₂O→MgCl₂.6H₂O            -   Regeneration of MgCl₂.6H₂O, return to #1.    -   b) Partial decomposition (“the CaSiO₃—Mg(OH)Cl process”):        -   1) 2×[MgCl₂.6H₂O+Δ→Mg(OH)Cl+5H₂O↑+HCl↑]            -   Thermal decomposition.            -   Twice as much MgCl₂.6H₂O is needed to trap the same                amount of CO₂.        -   2) 2HCl(aq)+CaSiO₃→CaCl₂(aq)+SiO₂↓+H₂O            -   Rock melting reaction.        -   3) 2Mg(OH)Cl+CaCl₂(aq)+CO₂→CaCO₃↓2MgCl₂(aq)+H₂O CO₂ capture            reaction        -   4) 2 MgCl₂+12H₂O→2MgCl₂.6H₂O            -   Regeneration of MgCl₂.6H₂O, return to #1.

II) Mg Only Process

Overall reaction MgSiO₃+CO₂→MgCO₃+SiO₂

-   -   c) Full decomposition (“the MgSiO₃—MgO process”)        -   1) 2HCl(aq)+MgSiO₃+(x−1)H₂O→MgCl₂+SiO₂↓+xH₂O            -   Rock melting reaction.        -   2) MgCl₂—xH₂O+Δ→MgO+(x−1)H₂O↑+2HCl↑            -   Thermal decomposition reaction.            -   Note “x−1” moles H₂O will be produced per 2 moles of                HCl.        -   3) MgO+CO₂→MgCO₃            -   CO₂ capture reaction.

Note, in this embodiment no recycle of MgCl₂ is required. The value ofx, the number of waters of hydration is much lower than 6 because theMgCl₂ from the rock melting reaction is hot enough to drive much of thewater into the vapor phase. Therefore the path from the rock meltingruns at steady state with “x” as modeled with a value of approximately2.

-   -   d) Partial decomposition (“the MgSiO₃—Mg(OH)Cl process”)        -   1) 2HCl(aq)+MgSiO₃→MgCl₂+SiO₂↓+H₂O            -   Rock melting reaction.            -   Note “x−1” H₂O will be present per mole of HCl during                the reaction.        -   2) 2×[MgCl₂.xH₂O+Δ→Mg(OH)Cl+(x−1)H₂O↑+HCl↑]            -   Decomposition.            -   Twice as much MgCl₂.(x−1)H₂O is needed to trap the same                amount of CO₂.        -   3) 2Mg(OH)Cl+CO₂→MgCO₃↓+MgCl₂+H₂O            -   CO₂ capture reaction.        -   4) MgCl₂(aq)+6H₂O→MgCl₂.6H₂O            -   Regenerate MgCl₂.6H₂O, Return to #1.

Note, in this embodiment half of the MgCl₂ is recycled. The value of x,the number of waters of hydration is somewhat lower than 6 because halfof the MgCl₂ is from the rock melting reaction which is hot enough todrive much of the water into the vapor phase and the remaining half isrecycled from the absorption column. Therefore the number of hydrationsfor the total amount of MgCl₂ at steady state will have a value ofapproximately 4, being the average between the MgCl₂.6H₂O andMgCl₂.2H₂O.

III) Diopside or Mixed Process:

Note diopside is a mixed calcium and magnesium silicate and dolomite isa mixed calcium and magnesium carbonate.

Overall reaction: ½ CaMg(SiO₃)₂+CO₂→½ CaMg(CO₃)₂+SiO₂

-   -   e) Full decomposition (“the Diopside-MgO process”):        -   1) MgCl₂.6H₂O+Δ→MgO+5H₂O↑+2HCl↑            -   Thermal decomposition.        -   2) HCl+½ CaMg(SiO₃)₂½ CaCl₂+½ MgSiO₃↓+½ SiO₂↓+½H₂O            -   First rock melting reaction.        -   3) HCl+½ MgSiO₃→½ MgCl₂+½ SiO₂↓+½ H₂O            -   Second rock melting reaction. The MgCl₂ returns to #1.        -   4) MgO+½ CaCl₂+CO₂→½ CaMg(CO₃)₂↓+½ MgCl₂        -   5) ½ MgCl₂+3H₂O→½ MgCl₂.6H₂O            -   Regenerate MgCl₂.6H₂O, return to #1.    -   f) Partial decomposition (“the Diopside-Mg(OH)Cl process”):        -   1) 2×[MgCl₂.6H₂O+Δ→Mg(OH)Cl+5H₂O↑+HCl↑]            -   Thermal decomposition.            -   Twice as much MgCl₂.6H₂O is needed to trap the same                amount of CO₂.        -   2) HCl+½ CaMg(SiO₃)₂→½ CaCl₂+½ MgSiO₃↓+½ SiO₂↓+½ H₂O            -   First rock melting reaction.        -   3) HCl+½ MgSiO₃→½ MgCl₂+½ SiO₂↓+½ H₂O            -   Second rock melting reaction. Here the MgCl₂ returns to                #1.        -   4) 2Mg(OH)Cl+½ CaCl₂+CO₂→½ CaMg(CO₃)₂↓+ 3/2 MgCl₂+H₂O        -   5) 3/2 MgCl₂+9H₂O→ 3/2 MgCl₂.6H₂O            -   Regenerate MgCl₂.6H₂O, return to #1

TABLE 9 Summary of Processes Detailed mass and Flue gas energy balanceof Example Process source Temp. ° C.¹ % CO₂ of flue gas² each processstream 10 CaSiO₃—Mg(OH)Cl Coal 320-550 7.2%-18% Table 14 11CaSiO₃—Mg(OH)Cl Nat. gas 600 7.2%-18% Table 14 12 CaSiO₃—MgO Coal 5507.2%-18% Table 15 13 CaSiO₃—MgO Nat. gas 600 7.2%-18% Table 15 14MgSiO₃—Mg(OH)Cl Coal 320-550 7.2%-18% Table 16 15 MgSiO₃—Mg(OH)Cl Nat.gas 600 7.2%-18% Table 16 16 MgSiO₃—MgO Coal 550 7.2%-18% Table 17 17MgSiO₃—MgO Nat. gas 600 7.2%-18% Table 17 18 Diopside-Mg(OH)Cl Coal320-550 7.2%-18% Table 18 19 Diopside-Mg(OH)Cl Nat. gas 600 7.2%-18%Table 18 20 Diopside-MgO Coal 550 7.2%-18% Table 19 21 Diopside-MgO Nat.gas 600 7.2%-18% Table 19 ¹The temperature range of 320-550° C. includesmodels run at 320, 360, 400, 440 and 550° C. respectively. ²The CO₂percentage of flue gas 7.2%-18% includes models run at 7.2%, 10%, 14%and 18% respectively.

Calcium Silicate Process:

The CaSiO₃—MgO and CaSiO₃—Mg(OH)Cl decomposition processes are furtherdivided into two stages, the first step consists of a dehydrationreaction where MgCl₂.6H₂O is converted to MgCl₂.2H₂O+4 H₂O and thesecond step in which the MgCl₂.2H₂O is converted to Mg(OH)Cl+HCl+H₂O ifpartial decomposition is desired or required and MgO+2HCl+H₂O if totaldecomposition is desired or required. FIG. 15 describes a layout of thisprocess.

Magnesium Silicate Process:

The MgSiO₃—MgO and MgSiO₃—Mg(OH)Cl processes consists of a one chamberdecomposition step in which the HCl from the decomposition chamberreacts with MgSiO₃ in the rock-melting reactor and the ensuing heat ofreaction leaves the MgCl₂ in the dihydrate form MgCl₂.2H₂O as it leavesthe rock-melting chamber in approach to the decomposition reactor whereit is converted to either MgO or Mg(OH)Cl as described earlier. Thisprocess may be preferred if calcium silicates are unavailable. The HClemitted from the decomposition reacts with MgSiO₃ to form more MgCl₂.The magnesium silicate process follows a different path from thecalcium. The process starts from the “rock melting reactionHCl+silicate”, and then moves to the “decomposition reaction(MgCl₂+heat),” and lastly the absorption column. In the calcium silicateprocess, all the magnesium compounds rotate between the decompositionreaction and the absorption reaction. FIG. 16 describes the layout ofthis process.

Mixed Magnesium and Calcium Silicate “Diopside” Process:

The intermediate process Diopside-MgO and Diopside-Mg(OH)Cl also involvea two stage decomposition consisting of the dehydration reactionMgCl₂.6H₂O+Δ→MgCl₂.2H₂O+4 H₂O followed by the decomposition reactionMgCl₂.2H₂O+Δ→MgO+2HCl+H₂O (full decomposition) orMgCl₂.2H₂O+Δ→Mg(OH)Cl+HCl+H₂O partial decomposition. FIG. 17 describes alayout of this process.

The ensuing HCl from the decomposition then reacts with the DiopsideCaMg(SiO₃)₂ in a two step “rock melting reaction.” The first reactioncreates CaCl₂ through the reaction2HCl+CaMg(SiO₃)₂→CaCl₂(aq)+MgSiO₃↓+SiO₂ ↓+H₂O. The solids from theprevious reaction are then reacted with HCl a second time to produceMgCl₂ through the reaction MgSiO₃+2HCl→MgCl₂+SiO₂↓+H₂O. The CaCl₂ fromthe first rock melter is transported to the absorption column and theMgCl₂ from the second rock melter is transported to the decompositionreactor to make Mg(OH)Cl or MgO.

Basis of the Reaction:

All of these examples assume 50% CO₂ absorption of a reference flue gasfrom a known coal fired plant of interest. This was done to enable acomparison between each example. The emission flow rate of flue gas fromthis plant is 136,903,680 tons per year and the CO₂ content of this gasis 10% by weight. This amount of CO₂ is the basis for examples 10through 21 which is:

Amount of CO₂ present in the flue gas per year:

-   -   136,903,680 tons per year*10%=13,690,368 tons per year

Amount of CO₂ absorbed per year.

-   -   13,690,368 tons per year*50%=6,845,184 tons per year of CO₂.

Since the amount of CO₂ absorbed is a constant, the consumption ofreactants and generation of products is also a constant depending on thereaction stoichiometry and molecular weight for each compound.

For all the examples of both the CaSiO₃—MgO and the CaSiO₃—Mg(OH)Clprocess (examples 10-13) the overall reaction is:

CaSiO₃+CO₂→CaCO₃+SiO₂

For all the examples of both the MgSiO₃—MgO and the MgSiO₃—Mg(OH)Clprocess (examples 14-17) the overall reaction is:

MgSiO₃+CO₂MgCO₃+SiO₂

For all the examples of both the Diopside-MgO and the Diopside-Mg(OH)Clprocess (examples 18-21) the overall reaction is:

½CaMg(SiO₃)₂+CO₂→½CaMg(CO₃)₂+SiO₂

The Aspen model enters the required inputs for the process andcalculates the required flue gas to provide the heat needed for thedecomposition reaction to produce the carbon dioxide absorbing compoundsMgO, Mg(OH)₂ or Mg(OH)Cl. This flue gas may be from a natural gas or acoal plant and in the case of coal was tested at a range of temperaturesfrom 320° C. to 550° C. This flue gas should not be confused with thereference flue gas which was used a standard to provide a specificamount of CO₂ removal for each example. A process with a highertemperature flue gas would typically require a lesser amount of flue gasto capture the same amount of carbon dioxide from the basis. Also a fluegas with a greater carbon dioxide concentration would typically resultin greater amount of flue gas needed to capture the carbon dioxidebecause there is a greater amount of carbon dioxide that needs to becaptured.

The consumption of reactants and generation of products can bedetermined from the basis of CO₂ captured and the molecular weights ofeach input and each output for each example.

TABLE 10 Molecular Masses of Inputs and Outputs (all embodiments).Compound Molecular Weight CaSiO₃ 116.16 MgSiO₃ 99.69 Diopside* 215.85CaCO₃ 100.09 MgCO₃ 84.31 Dolomite* 184.40 SiO₂ 60.08 CO₂ 44.01 *Numberof moles must be divided by 2 to measure comparable CO₂ absorption withthe other processes,

For Examples 10-13:

The CaSiO₃ consumption is:

-   -   6,845,184 tons per year*(116.16/44.01)=18,066,577 tons per year.

The CaCO₃ production is:

-   -   6,845,184 tons per year*(100.09/44.01)=15,559,282 tons per year.

The SiO₂ production is:

-   -   6,845,184 tons per year*(60.08/44.01)=9,344,884 tons per year

The same type of calculations may be done for the remaining examples.This following table contains the inputs and outputs for examples 10through 21. Basis: 6,845,184 tons CO₂ absorbed per year.

TABLE 11 Mass Flows of Inputs and Outputs for Examples 10-21. Allmeasurements are in tons per year (TPY) Examples 10-13 14-17 18-21 CO₂absorbed 6,845,184 6,845,184 6,845,184 INPUTS Flue Gas for CO₂ Capture136,903,680 136,903,680 136,903,680 10% CO₂ 13,690,368 13,690,36813,690,368 CaSiO₃ 18,066,577 MgSiO₃ 15,613,410 Diopside 16,839,993OUTPUTS SiO₂ 9,344,884 9,344,884 9,344,884 CaCO₃ 15,559,282 MgCO₃13,111,817 Dolomite 14,319,845

Running the Aspen models generated the following results for the heatduty for each step of the decomposition reaction, dehydration anddecomposition. The results for each example are summarized in the tablebelow.

TABLE 12 Power (Rate of Energy for each process at the particular basisof CO₂ absorption). HEAT BALANCE Process CaSiO₃—Mg(OH)Cl CaSiO₃—MgOMgSiO₃—Mg(OH)Cl MgSiO₃—MgO Diop.-Mg(OH)Cl Diop.-MgO Examples 10, 11 12,13 14, 15 16, 17 18, 19 20, 21 Dehydration Chamber (MW) 2670 1087 n/an/a 2614 1306 HEX TO DI (210° C.) Source HCl reacting with silicateDecomposition Chamber (MW) 1033 1297 1226 1264 1231 1374 DecompositionTemp. ° C. 210 450 210 450 210 450 Source Flue Gas Total heat used forD&D* (MW) 3703 2384 1226 1264 3854 2680 *D&D equals dehydration anddecomposition

TABLE 13 Percentage CO₂ captured as a function of flue gas temperatureand CO₂ concentration. Examples 10 through 13. Process CaSiO₃—Mg(OH)ClCaSiO₃—MgO CaSiO₃—Mg(OH)Cl CaSiO₃—MgO Flue Gas Source/Temp. Coal CoalCoal Coal Coal Coal Nat. gas Nat. gas 320° C. 360° C. 400° C. 440° C.550° C. 550° C. 600° C. 600° C. Example # % CO₂ 10 10 10 10 10 12 11 13 7% 33% 45% 57% 70% 105%  83% 121%  96% 10% 24% 32% 41% 50% 75% 60% 87%69% 14% 17% 23% 29% 36% 54% 43% 62% 50% 18% 13% 18% 23% 28% 42% 33% 48%39%

A value of over 100% means that excess heat is available to produce moreMg(OH)Cl or MgO. FIG. 24 illustrates the percent CO₂ captured forvarying CO₂ flue gas concentrations, varying temperatures, whether theflue gas was originated from coal or natural gas, and also whether theprocess relied on full or partial decomposition for examples 10 through13 of the CaSiO₃—Mg(OH)Cl and CaSiO₃—MgO processes.

TABLE 14 Percentage CO₂ captured as a function of flue gas temperatureand CO₂ concentration. Examples 14 through 17. Process MgSiO₃—Mg(OH)ClMgSiO₃—MgO MgSiO₃—Mg(OH)Cl MgSiO₃—MgO Flue Gas Source/Temp. Coal CoalCoal Coal Coal Coal Ngas Ngas 320° C. 360° C. 400° C. 440° C. 550° C.550° C. 600° C. 600° C. Example # % CO₂ 14 14 14 14 14 16 15 17  7% 24%34% 45% 55% 84% 86% 93% 96% 10% 17% 25% 32% 40% 61% 62% 67% 69% 14% 12%18% 23% 28% 43% 44% 48% 49% 18% 10% 14% 18% 22% 34% 34% 37% 38%

FIG. 25 illustrates the percent CO₂ captured for varying CO₂ flue gasconcentrations, varying temperatures, whether the flue gas wasoriginated from coal or natural gas, and also whether the process reliedon full or partial decomposition for examples 14 through 17 of theMgSiO₃—Mg(OH)Cl and MgSiO₃—MgO processes.

TABLE 15 Percentage CO₂ captured as a function of flue gas temperatureand CO₂ concentration. Examples 18 through 21. Process Diop -Diopside-Mg(OH)Cl Diop - MgO Mg(OH)Cl Diop-MgO Flue Gas Source/Temp.Coal Coal Coal Coal Coal Coal Ngas Ngas 320° C. 360° C. 400° C. 440° C.550° C. 550° C. 600° C. 600° C. Example # % CO₂ 18 18 18 18 18 20 19 21 7% 28% 38% 48% 59% 88% 79% 101%  91% 10% 20% 27% 35% 42% 63% 57% 73%65% 14% 14% 19% 25% 30% 45% 40% 52% 47% 18% 11% 15% 19% 23% 35% 31% 41%36% * Note Diop equals Diopside

FIG. 26 illustrates the percent CO₂ captured for varying CO₂ flue gasconcentrations, varying temperatures, whether the flue gas wasoriginated from coal or natural gas, and also whether the process reliedon full or partial decomposition for examples 18 through 21 of theDiopside—Mg(OH)Cl and Diopside—MgO processes.

TABLE 16a Mass and Energy Accounting for Examples 10 and 11 Simulation.Process Stream Names 1 2 CaCl₂ CaCl₂—Si CaCO₃ CaSiO₃ FLUEGAS H₂O HCl HClVapor PH Temperature 112.6 95 149.9 150 95 25 100 25 200 250 ° C.Pressure psia 14.696 15 100 14.696 14.7 14.696 15.78 14.7 14.696 14.696Mass VFrac 0 0.793 0 0 0 0 1 0 1 1 Mass SFrac 1 0.207 0 0.163 1 1 0 0 00 Mass Flow 5.73E+07 3.96E+07 4.36E+07 5.21E+07 1.41E+07  164E+076.21E+07 1.80E+07 3.57E+07 3.57E+07 tonne/year Volume 11216.8  2.2E+0717031.4 18643.542 2616.633 2126.004 3.11E+07 502184.16 3.30E+07 3.65E+07Flow gal/min Enthalpy −22099.5 −3288.21 −17541.7 −21585.353 −5368.73−7309.817 −2926.806 −9056.765 −11331.898 −11240.08 MW Density 160.3710.059 80.305 87.619 169.173 241.725 0.063 1.125 0.034 0.031 lb/cuft H₂O0 1.80E+07 2.79E+07 2.79E+07 0 0 3.10E+06 1.80E+07 2.54E+07 2.54E+07 HCl0 0 0.004 0.004 0 0 0 0 1.03E+07 1.03E+07 CO₂ 0 0 0 0 0 0 6.21E+06 0 0 0O₂ 0 0 0 0 0 0 6.21E+06 0 0 0 N₂ 0 0 0 0 0 0 4.65E+07 0 0 0 CaCO₃ 0 0 00 1.41E+07 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 0 00 MgCl₂*2W 0 0 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 0 0 MgCl₂*6W5.73E+07 0 0 0 0 0 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 0 0 0 Mg(OH)₂ 08.22E+06 0 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 00 0 0 SO₂ 0 0 0 0 0 0 0 0 0 0 NO₂ 0 0 0 0 0 0 0 0 0 0 NO 0 0 0 0 0 0 0 00 0 Mg²⁺ 0 3.43E+06 0 0 0 0 0 0 0 0 Ca²⁺ 0 0 5.65E+06 5.65E+06 0 0 0 0 00 Cl⁻ 0 1.00E+07 1.00E+07 1.00E+07 0 0 0 0 0 0 CO3²⁻ 0 0 0 0 0 0 0 0 0 0HCO₃ ⁻ 0 0 0 0 0 0 0 0 0 0 OH⁻ 0 0 0 0 0 0 0 0 0 0 CaSiO₃ 0 0 0 .007 01.64E+07 0 0 0 0 SiO₂ 0 0 0 8.47E+06 0 0 0 0 0 0

TABLE 16b Mass and Energy Accounting for Examples 10 and 11 Simulation.Process Stream Names MgCl₂—2W MgCl₂—6W RECYCLE1 RX2-VENT SiO₂ SLURRYSOLIDS-1 SOLIDS-2 PH 9.453 9.453 Temperature C. 215 80 95 95 149.9 95250 115 Pressure psia 14.696 14.696 14.7 14.7 100 14.7 14.696 14.696Mass VFrac .502 0 0 1 0 0 0 .165 Mass SFrac .498 1 0 0 1 .152 1 .207Mass Flow tonne/year 5.73E+07 5.73E+07 7.84E+07 5.27E+07 8.47E+069.26E+07 2.16E+07 3.96E+07 Volume Flow gal/min 3.03E+07 11216.79633789.492  282E+07 1607.826 32401.78 3828.933 6.33E+06 Enthalpy MW−1877.989 −22191.287 −32705.27 120.09 0 −38074.2 −7057.97 −4070.06Density lb/cuft .059 160.371 72.846 0.059 165.327 89.628 177.393 0.197H₂O 2.54E+07 0 5.16E+07 0 0 5.16E+07 0 1.80E+07 HCl 3.40E+06 0 0 0 0 0 00 CO₂ 0 0 0.074 25.781 0 0.074 0 0 O₂ 0 0 2510.379 6.20E+06 0 2510.379 00 N₂ 0 0 8109.244 4.65E+07 0 8109.245 0 0 CaCO₃ 0 0 0 0 0 1.41E+07 0 0MgCl₂ 0 0 0 0 0 0 0 0 MgCl₂*W 2.14E+07 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 00 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 MgCl₂*6W 0 5.73E+07 0 0 0 0 0 0 Mg(OH)Cl7.15E+06 0 0 0 0 0 2.16E+07 0 Mg(OH)₂ 0 0 0 0 0 0 0 8.22E+06 MgO 0 0 0 00 0 0 0 MgHCO₃ ⁺ 0 0 3324.433 0 0 3324.433 0 0 SO₂ 0 0 0 0 0 0 0 0 NO₂ 00 0 0 0 0 0 0 NO 0 0 0 0 0 0 0 0 Mg²⁺ 0 0 6.85E+06 0 0 6.85E+06 03.43E+06 Ca²⁺ 0 0 1644.031 0 0 1644.031 0 0 Cl⁻ 0 0 2.00E+07 0 02.00E+07 0 1.00E+07 CO₃ 0 0 61.424 0 0 61.424 0 0 HCO₃ 0 0 27.297 0 027.297 0 0 OH⁻ 0 0 690.278 0 0 690.278 0 0 CaSiO₃ 0 0 0 0 0.007 0 0 0SiO₂ 0 0 0 0 8.47E+06 0 0 0

TABLE 17a Mass and Energy Accounting for Examples 12 and 13 Simulation.Process Stream Names 1 2 CaCl₂ CaCl₂—Si CaCO₃ CaSiO₃ FLUEGAS H₂O HCl HClVapor PH Temperature 271 255.5 149.8 150 95 25 100 25 200 450 ° C.Pressure psia 14.696 15 100 14.696 14.7 14.696 15.78 14.7 14.696 14.696Mass VFrac 0 0 0 0 0 0 1 0 1 1 Mass SFrac 1 1 0 0.215 1 1 0 0 0 0 MassFlow 2.87E+07 2.37E+07 3.09E+07 3.94E+07 1.41E+07 1.64E+07 6.21E+071.80E+07 2.30E+07 2.30E+07 tonne/year Volume Flow 5608.398 10220.83510147.12 11758.176 2616.827 2126.004 3.11E+07 502184.16 1.93E+072.94E+07 gal/min Enthalpy MW −10826.6 −11660.74 −11347.9 −15391.633−5369.12 −7309.817 −2926.806 −9056.765 −6056.076 −5786.994 Densitylb/cuft 160.371 72.704 95.515 105.035 169.173 241.725 0.063 1.125 0.0370.024 H₂O 0 1.55E+07 1.52E+07 1.52E+07 0 0 3.10E+06 1.80E+07 1.27E+071.27E+07 HCl 0 0 0.015 0.015 0 0 0 0 1.03E+07 1.03e+07 CO₂ 0 0 0 0 0 06.21E+06 0 0 0 O₂ 0 0 0 0 0 0 6.21E+06 0 0 0 N₂ 0 0 0 0 0 0 4.65E+07 0 00 CaCO₃ 0 0 0 0 1.41E+07 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 0 0 0 MgCl₂*W 0 00 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 0 00 MgCl₂*6W 2.87E+07 0 0 0 0 0 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 0 0 0Mg(OH)₂ 0 8.22E+06 0 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 00 0 0 0 0 0 0 0 SO₂ 0 0 0 0 0 0 0 0 0 0 NO₂ 0 0 0 0 0 0 0 0 0 0 NO 0 0 00 0 0 0 0 0 0 Mg²⁺ 0 0 0 0 0 0 0 0 0 0 Ca²⁺ 0 0 5.65E+06 5.65E+06 0 0 00 0 0 Cl⁻ 0 0 1.00E+07 1.00E+07 0 0 0 0 0 0 CO₃ ²⁻ 0 0 0 0 0 0 0 0 0 0HCO₃ ⁻ 0 0 0 0 0 0 0 0 0 0 OH⁻ 0 0 0 0 0 0 0 0 0 0 CaSiO₃ 0 0 0 0.0231.64E+07 0 0 0 0 0 SiO₂ 0 0 0 8.47E+06 0 0 0 0 0 0

TABLE 17b Mass and Energy Accounting for Examples 12 and 13 Simulation.Process Stream Names MgCl₂—2W MgCl₂—6W RECYCLE1 RX2-VENT SiO₂ PH 9.304Temperature ° C. 215  80 95 95 149.8 Pressure psia   14.696 14.696 14.714.7 100 Mass VFrac    0.502 0 0 1 0 Mass SFrac    0.498 1 0 0 1 MassFlow tonne/year      2.87E+07 2.87E+07 4.98E+07 5.27E+07 8.47E+06 VolumeFlow gal/min      1.51E+07 5608.398 25330.305 2.82E+07 1607.826 EnthalpyMW −9388.949  −11095.644 −21589.89 120.08 0 Density lb/cuft    0.059160.371 61.662 0.059 165.327 H₂O   127E+07 0 3.63E+07 0 0 HCl     1.70E+07 0 0 0 0 CO₂ 0 0 0.145 79.255 0 O₂ 0 0 1919.222 6.20E+06 0N₂ 0 0 6199.3 4.65E+07 0 CaCO₃ 0 0 0 0 0 MgCl₂ 0 0 0 0 0 MgCl₂*W     1.07E+07 0 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 MgCl₂*6W 02.87E+07 0 0 0 Mg(OH)Cl      3.58E+06 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 00 0 0 MgHCO₃ ⁺ 0 0 2208.676 0 0 SO₂ 0 0 0 0 0 NO₂ 0 0 0 0 0 NO 0 0 0 0 0Mg²⁺ 0 0 3.43E+06 0 0 Ca²⁺ 0 0 1225.309 0 0 Cl⁻ 0 0 1.00E+07 0 0 CO₃ ²⁻0 0 110.963 0 0 HCO₃ ⁻ 0 0 63.12 0 0 OH⁻ 0 0 519.231 0 0 CaSiO₃ 0 0 0 00.023 SiO₂ 0 0 0 0 8.47E+06 Process Stream Names SLURRY SOLIDS-1SOLIDS-2 PH 9.304 Temperature ° C. 95 450 115 Pressure psia 14.7 14.69614.696 Mass VFrac 0 0 0 Mass SFrac 0.221 1 1 Mass Flow tonne/year6.39E+07 5.68E+06 2.37E+07 Volume Flow gal/min 22988.79 797.11 10220.84Enthalpy MW −26959.3 −2603.98 −11955.9 Density lb/cuft 87.199 223.69572.704 H₂O 3.63E+07 0 1.55E+07 HCl 0 0 0 CO₂ 0.145 0 0 O₂ 1919.222 0 0N₂ 6199.301 0 0 CaCO₃ 1.41E+07 0 0 MgCl₂ 0 0 0 MgCl₂*W 0 0 0 MgCl₂*2W 00 0 MgCl₂*4W 0 0 0 MgCl₂*6W 0 0 0 Mg(OH)Cl 0 0 0 Mg(OH)₂ 0 0 8.22E+06MgO 0 5.68E+06 0 MgHCO₃ ⁺ 2208.676 0 0 SO₂ 0 0 0 NO₂ 0 0 0 NO 0 0 0 Mg²⁺3.43E+06 0 0 Ca²⁺ 1225.309 0 0 Cl⁻ 1.00E+07 0 0 CO₃ ²⁻ 110.963 0 0 HCO₃⁻ 63.12 0 0 OH⁻ 519.231 0 0 CaSiO₃ 0 0 0 SiO₂ 0 0 0

TABLE 18a Mass and Energy Accounting for Examples 14 and 15 Simulation.Process Stream Names FLUEGAS H₂O H₂O HCl Vapor MgCl₂--2 MgCl₂—2wMgCl₂—Si PH Temperature ° C. 100 25 26 250 200.7 200 200 Pressure psia15.78 1 14.696 14.696 15 14.696 14.696 Mass VFrac 1 0 0.798 1 0.238 00.169 Mass SFrac 0 0 0.186 0 0 1 0.289 Mass Flow tons/year 1.37E+081.00E+07 1.58E+08 1.69E+07 2.31E+07 4.08E+07 3.26E+07 Volume Flowgal/min 62.21E+07 4569.619 4.91E+07 1.22E+07 5.22E+06 3828.933 5.33E+06Enthalpy MW −5853.92 −4563.814 −13984.7 −2861.732 0 −11194.13 −10932.15Density lb/cuft 0.063 62.249 0.091 0.04 0.126 303.28 0.174 H₂O 6.85E+061.00e+07 5.19E+06 5.60E+06 8.37E+06 0 8.37E+06 HCl 0 0 0 1.13E+07126399.9 0 126399.87 CO₂ 1.37E+07 0 6.85E+06 0 0 0 0 O₂ 1.37E+07 01.37E+07 0 0 0 0 N₂ 1.03E+08 0 1.03E+08 0 0 0 0 MgCO₃ 0 0 0 0 0 0 0MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 4.08E+07 0MgCl₂*4W 0 0 1.09E+07 0 0 0 0 MgCl₂*6W 0 0 1.83E+07 0 0 0 0 Mg(OH)Cl 0 00 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0.001 0 00 0 SO₂ 0 0 0 0 0 0 0 NO₂ 0 0 0 0 0 0 0 NO 0 0 0 0 0 0 0 Mg²⁺ 0 0 0 03.74E+06 0 3.74E+06 Cl⁻ 0 0 0 0 1.09E+07 0 1.09E+07 CO₃ ²⁻ 0 0 0 0 0 0 0HCO₃ ⁻ 0 0 0 0 0 0 0 OH⁻ 0 0 0 0 0 0 0 SiO₂ 0 0 0 0 0 0 9.24E+06 MgSiO₃0 0 0 0 0 0 174011.19

TABLE 18b Mass and Energy Accounting for Examples 14 and 15 Simulation.Process Stream Names MgCO₃ MgSiO₃ RX2-VENT SiO₂ SLURRY SOLIDS-1 SOLIDS-2PH .0864 6.24 Temperature ° C. 26 25 200.7 60 250 95 Pressure psia14.696 14.696 15 44.088 14.696 44.088 Mass VFrac 0 0 0 0 0 0 Mass SFrac1 1 1 0.248 1 0.268 Mass Flow tons/year 1.31E+07 1.56E+07 0 9.41E+061.71E+08 2.39E+07 3.39E+07 Volume Flow gal/min 1985.546 2126.0041613.601 178707.499 3828.933 8016.874 Enthalpy MW 0 −6925.208 0 0−18961.843 −7057.974 −12123.17 Density lb/cuft 187.864 208.902 165.96727.184 177.393 120.206 H₂O 0 0 0 5.19E+06 0 1.00E+07 HCl 0 0 0 0 0 0 CO₂0 0 0 6.85E+06 0 0 O₂ 0 0 0 1.37E+07 0 0 N₂ 0 0 0 1.03E+08 0 0 MgCO₃1.31E+07 0 0 1.31E+07 0 0 MgCl₂ 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 MgCl₂*2W0 0 0 0 0 0 MgCl₂*4W 0 0 0 1.09E+07 0 0 MgCl₂*6W 0 0 0 1.83E+07 0 0Mg(OH)Cl 0 0 0 0 2.39E+07 0 Mg(OH)₂ 0 0 0 0 0 9.07E+06 MgO 0 0 0 0 0 0MgHCO₃ ⁺ 0 0 0 0.001 0 0 SO₂ 0 0 0 0 0 0 NO₂ 0 0 0 0 0 0 NO 0 0 0 0 0 0Mg²⁺ 0 0 0 0 0 3.78E+06 Cl⁻ 0 0 0 0 0 1.10E+07 CO3²⁻ 0 0 0 0 0 0 HCO₃ ⁻0 0 0 0 0 0 OH⁻ 0 0 0 0 0 0.029 SiO₂ 0 0 9.24E+06 0 0 0 MgSiO₃ 01.56E+07 174011.19 0 0 0

TABLE 19a Mass and Energy Accounting for Examples 16 and 17 Simulation.Process Stream Names FLUEGAS H₂O H₂O HCl Vapor MgCl₂--2 MgCl₂—2wMgCl₂—Si PH 6.583 Temperature ° C. 100 25 59.6 450 200 200 200 Pressurepsia 15.78 1 14.696 14.696 15 14.696 14.696 Mass VFrac 1 0 0.004 1 0 0 0Mass SFrac 0 0 0 0 1 1 1 Mass Flow tons/year 1.37E+08 1.00E+07 1.70E+071.41E+07 2.04E+07 2.04E+07 2.98e+07 Volume Flow gal/min 6.21E+074569.619 40446.86 1.26E+07 1914.466 1914.466 3522.292 Enthalpy MW−5853.92 −4563.814 −7633.28 −1728.6 0 −5597.066 −9628.072 Densitylb/cuft 0.063 62.249 11.94 0.032 303.28 303.28 240.308 H₂O 685.E+061.00E+07 1.68E+07 2.80E+06 0 0 0 HCl 0 0 0 1.13E+07 0 0 0 CO₂ 1.37E+07 056280.04 0 0 0 0 O₂ 1.37E+07 0 18848.97 0 0 0 0 N₂ 1.03E+08 0 56346.51 00 0 0 MgCO₃ 0 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0MgCl₂*2W 0 0 0 0 2.04E+07 2.04E+07 2.04E+07 MgCl₂*4W 0 0 0 0 0 0 0MgCl₂*6W 0 0 0 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 0 0 MgO0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 77.467 0 0 0 0 SO₂ 0 0 0 0 0 0 0 NO₂ 0 0 0 00 0 0 NO 0 0 0 0 0 0 0 Mg²⁺ 0 0 744.857 0 0 0 0 Cl⁻ 0 0 0 0 0 0 0 CO₃ ²⁻0 0 1.19 0 0 0 0 HCO₃ ⁻ 0 0 3259.779 0 0 0 0 OH⁻ 0 0 0.109 0 0 0 0 SiO₂0 0 0 0 0 0 9.34E+06 MgSiO₃ 0 0 0 0 0 0 0

TABLE 19b Mass and Energy Accounting for Examples 16 and 17 Simulation.Process Stream Names MgCO₃ MgSiO₃ RX2-VENT SiO₂ SLURRY SOLIDS-1 SOLIDS-2PH 6.583 8.537 Temperature ° C. 59.6 25 60 200 60 450 95 Pressure psia14.696 14.696 44.088 15 44.088 14.696 44.088 Mass VFrac 0 0 1 0 0 0 0Mass SFrac 1 1 0 1 0.436 1 0.558 Mass Flow tons/year 1.31E+07 1.56E+071.23E+08 9.34E+06 3.01E+07 6.27E+06 1.63E+07 Volume Flow gal/min1983.661 2126.004 1.76E+07 1607.826 9945.342 797.11 5155.55 Enthalpy MW0 −6925.208 −1613.054 0 −12593.788 −2603.979 −7331.893 Density lb/cuft187.864 208.902 0.199 165.327 86.031 223.695 89.76 H₂O 0 0 0 0 1.68E+070 7.20E+06 HCl 0 0 0 0 0 0 0 CO₂ 0 0 6.78E+06 0 56280.036 0 0 O₂ 0 01.37E+07 0 18848.966 0 0 N₂ 0 0 1.03E+08 0 56346.51 0 0 MgCO₃ 1.31E+07 00 0 1.31E+07 0 0 MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 MgCl₂*2W 0 00 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0 0 0 Mg(OH)Cl 0 0 0 00 0 0 Mg(OH)₂ 0 0 0 0 0 0 9.07E+06 MgO 0 0 0 0 0 6.27E+06 0 MgHCO₃ ⁺ 0 0343.415 0 77.467 0 0 SO₂ 0 0 0 0 0 0 0 NO₂ 0 0 0 0 0 0 0 NO 0 0 0 0 0 00 Mg²⁺ 0 0 2722.849 0 744.857 0 14.282 Cl⁻ 0 0 0 0 0 0 0 CO₃ ²⁻ 0 04.344 0 1.19 0 0 HCO₃ ⁻ 0 0 14439.982 0 3259.779 0 0 OH⁻ 0 0 0.481 00.109 0 19.989 SiO₂ 0 0 0 9.34E+06 0 0 0 MgSiO₃ 0 1.56E+07 0 0 0 0 0

TABLE 20a Mass and Energy Accounting for Examples 18 and 19 Simulation.Process Stream Names 5 CaCl₂—2W FLUEGAS H₂O HCl HCl-VENT HCIVAP2 PHTemperature ° C. 200 160 100 25 250 100 349.1 Pressure psia 14.69614.696 15.78 1 14.696 14.696 14.696 Mass VFrac 0.378 0.473 1 0 1 1 1Mass SFrac 0.622 0 0 0 0 0 0 Mass Flow 6.32E+07 2.40E+07 1.37E+081.00E+07 3.94E+07 0.001 197E+07 tons/year Volume Flow 2.29E+07 1.02E+076.21E+07 4569.619 3.64E+07 0.001 1.82E+07 gal/min Enthalpy MW −19530.7−8042.026 −5853.92 −4563.814 −11241.7 0 −5620.856 Density lb/cuft 0.0790.067 0.063 62.249 0.031 0.075 0.031 H₂O 2.29E+07 1.54E+07 6.85E+061.00E+07 2.08E+07 0 1.40E+07 HCl 983310.7 0 0 0 1.13E+07 0.001 5.67E+06CO₂ 0 0 1.37E+07 0 0 0 0 O₂ 0 0 1.37E+07 0 0 0 0 N₂ 0 0 1.03E+08 0 0 0 0MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 MgCl₂*2W 3.73E+07 0 0 0 0 0 0MgCl₂*4W 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0 0 0 Mg(OH)Cl 2.07E+06 0 0 0 00 0 Mg(OH)₂ 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 0 SO₂ 00 0 0 0 0 0 NO₂ 0 0 0 0 0 0 0 NO 0 0 0 0 0 0 0 Mg²⁺ 0 2494.617 0 0 0 0 0Ca²⁺ 0 3.11E+06 0 0 0 0 0 Cl⁻ 0 5.51E+06 0 0 0 0 0 CO₃ ²⁻ 0 0 0 0 0 0 0HCO₃ ⁻ 0 0 0 0 0 0 0 OH⁻ 0 0 0 0 0 0 0 CaSiO₃ 0 0 0 0 0 0 0 SiO₂ 0 0 0 00 0 0 MgSiO₃ 0 0 0 0 0 0 0 DIOPSIDE 0 0 0 0 0 0 0 DOLOMITE 0 0 0 0 0 0 0Process Stream Names HCl Vapor HClVENT2 MELT1 MELT2 MELT3 PH Temperature° C. 349.1 160 160 160 100 Pressure psia 14.696 14.696 14.696 14.69614.696 Mass VFrac 1 1 0.311 0 0 Mass SFrac 0 0 0.342 1 0.291 Mass Flowtons/year 1.97E+07 26.688 3.65E+07 1.25E+07 3.22E+07 Volume Flow gal/min1.82E+07 11.834 1.02E+07 1866.916 9636.543 Enthalpy MW −5620.856 −0.002−13498.19 −5456.154 −12759.563 Density lb/cuft 0.031 0.064 0.102 190.16394.933 H₂O 1.40E+07 0 1.54E+07 0 1.54E+07 HCl 5.67E+06 26.688 26.688 00.001 CO₂ 0 0 0 0 0 O₂ 0 0 0 0 0 N₂ 0 0 0 0 0 MgCl₂ 0 0 0 0 0 MgCl₂*W 00 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0SO₂ 0 0 0 0 0 NO₂ 0 0 0 0 0 NO 0 0 0 0 0 Mg²⁺ 0 0 2494.617 0 1.89E+06Ca²⁺ 0 0 3.11E+06 0 4128.267 Cl⁻ 0 0 5.51E+06 0 5.51E+06 CO₃ ²⁻ 0 0 0 00 HCO₃ ⁻ 0 0 0 0 0 OH⁻ 0 0 0 0 0 CaSiO₃ 0 0 11965.659 11965.659 0 SiO₂ 00 4.67E+06 4.67E+06 9.34E+06 MgSiO₃ 0 0 7.80E+06 7.80E+06 36.743DIOPSIDE 0 0 0 0 0 DOLOMITE 0 0 0 0 0

TABLE 20b Mass and Energy Accounting for Examples 18 and 19 Simulation.Process Stream Names MgCaSiO₃ MgCl₂—H MgCl₂—H RECYCLE RECYCLE- SiO₂ PHTemperature ° C. 25  100 100 95 95 100 Pressure psia   14.696 14.69614.696 14.696 14.696 14.696 Mass VFrac 0 0 0 0 0 0 Mass SFrac 1 0 10.828 1 1 Mass Flow tons/year   168E+07 2.28E+07 4.74E+07 5.73E+071.58E+07 9.34E+06 Volume Flow gal/min  1063.002 8028.716 8412.59713075.55 2804.199 1607.827 Enthalpy MW −7167.458  0 −16601.2 −21023.6−5537.26 0 Density lb/cuft   450.627 80.836 160.371 124.605 160.371165.327 H₂O 0 1.54E+07 0 9.84E+07 0 0 HCl 0 0 0 0 0 0 CO₂ 0 0 0 0 0 0 O₂0 0 0 0 0 0 N₂ 0 0 0 0 0 0 MgCl₂ 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0MgCl₂*2W 0 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 0 MgCl₂*6W 0 0 4.74E+07 4.74E+071.58E+07 0 Mg(OH)Cl 0 0 0 0 0 0 Mg(OH)₂ 0 0 0 12011.06 0 0 MgO 0 0 0 0 00 MgHCO₃ ⁺ 0 0 0 11.135 0 0 SO₂ 0 0 0 0 0 0 NO₂ 0 0 0 0 0 0 NO 0 0 0 0 00 Mg2⁺ 0 1.89E+06 0 0 0 0 Ca²⁺ 0 4128.267 0 0 0 0 Cl⁻ 0 5.51E+06 0 4.6270 0 CO₃ ²⁻ 0 0 0 0 0 0 HCO₃ ⁻ 0 0 0 0 0 0 OH⁻ 0 0 0 0 0 0 CaSiO₃ 0 0 0 00 0 SiO₂ 0 0 0 0 0 9.34E+06 MgSiO₃ 0 0 0 0 0 36.743 DIOPSIDE     1.68E+07 0 0 0 0 0 DOLOMITE 0 0 0 0 0 0 Process Stream Names SLURRYSOLIDS SOLIDS-1 SOLIDS-2 VENT PH 5.163 6.252 Temperature ° C. 95 95 25095 95 Pressure psia 14.696 14.696 14.696 14.696 14.696 Mass VFrac 0 0 00 1 Mass SFrac 0.317 1 1 0.268 0 Mass Flow tons/year 1.95E+08 1.43E+072.39E+07 3.39E+07 1.23E+08 Volume Flow gal/min 185622 2276.765 3828.9338017.333 5.85E+07 Enthalpy MW −27714.4 0 −7057.97 −12113.4 −1510.76Density lb/cuft 29.855 178.921 177.393 120.2 0.06 H₂O 9.84E+06 0 01.00E+07 0 HCl 0 0 0 0 0 CO₂ 6.85E+06 0 0 0 6.85E+06 O₂ 1.37E+07 0 0 01.37E+07 N₂ 1.03E+08 0 0 0 1.03E+08 MgCl₂ 0 0 0 0 0 MgCl₂*W 0 0 0 0 0MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 MgCl₂*6W 4.74E+07 0 0 0 0 Mg(OH)Cl0 0 2.39E+07 0 0 Mg(OH)₂ 12011.06 0 0 9.07E+06 0 MgO 0 0 0 0 0 MgHCO₃ ⁺11.135 0 0 0 0 SO₂ 0 0 0 0 0 NO₂ 0 0 0 0 0 NO 0 0 0 0 0 Mg2⁺ 0 0 03.78E+06 0 Ca²⁺ 0 0 0 0 0 Cl⁻ 4.627 0 0 1.10E+07 0 CO₃ ²⁻ 0 0 0 0 0 HCO₃⁻ 0 0 0 0 0 OH⁻ 0 0 0 0.03 0 CaSiO₃ 0 0 0 0 0 SiO₂ 0 0 0 0 0 MgSiO₃ 0 00 0 0 DIOPSIDE 0 0 0 0 0 DOLOMITE 1.43E+07 1.43E+07 0 0 0

TABLE 21a Mass and Energy Accounting for Examples 20 and 21 Simulation.Process Stream Names 5 CaCl₂—2W FLUEGAS H₂O HCl HCl-VENT HClVAP2 PHTemperature ° C. 200 160 100 25 450 100 449.5 Pressure psia 14.69614.696 15.78 1 14.696 14.696 14.696 Mass VFrac 0.378 0.256 1 0 1 1 1Mass SFrac 0.622 0 0 0 0 0 0 Mass Flow tons/year 3.16E+07 1.70E+071.37E+08 1.00E+07 2.54E+07 0.006 1.27E+07 Volume Flow gal/min 1.14E+073.91E+06 6.21E+07 4569.619 2.94E+07 0.002 1.47E+07 Enthalpy MW −9765.36−5388.055 −5853.92 −4563.814 −5787.5 0 −2893.751 Density lb/cuft 0.0790.124 0.063 62.249 0.025 0.075 0.025 H₂O 1.15E+07 8.41E+06 6.85E+061.00E+07 1.40e+07 0 7.00E+06 HCl 491655.4 0 0 0 1.13E+07 0.006 5.67E+06CO₂ 0 0 1.37E+07 0 0 0 0 O₂ 0 0 1.37E+07 0 0 0 0 N₂ 0 0 1.03E+08 0 0 0 0MgCl₂ 0 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 0 MgCl₂*2W 1.86E+07 0 0 0 0 0 0MgCl₂*4W 0 0 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0 0 0 Mg(OH)Cl 1.04E+06 0 0 0 00 0 Mg(OH)₂ 0 0 0 0 0 0 0 MgO 0 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0 0 0 SO₂ 00 0 0 0 0 0 NO₂ 0 0 0 0 0 0 0 NO 0 0 0 0 0 0 0 Mg²⁺ 0 2494.624 0 0 0 0 0Ca²⁺ 0 3.11E+06 0 0 0 0 0 Cl⁻ 0 5.51E+06 0 0 0 0 0 CO₃ ²⁻ 0 0 0 0 0 0 0HCO₃ ⁻ 0 0 0 0 0 0 0 OH⁻ 0 0 0 0 0 0 0 CaSiO₃ 0 0 0 0 0 0 0 SiO₂ 0 0 0 00 0 0 MgSiO₃ 0 0 0 0 0 0 0 DIOPSIDE 0 0 0 0 0 0 0 DOLOMITE 0 0 0 0 0 0 0Process Stream Names HCl Vapor HClVENT2 MELT1 MELT2 MELT3 PH Temperature° C. 449.5 160 160 160 100 Pressure psia 14.696 14.696 14.696 14.69614.696 Mass VFrac 1 1 0.148 0 0 Mass SFrac 0 0 0.423 1 0.371 Mass Flowtons/year 1.27E+07 10.275 2.95E+07 1.25E+07 2.52E+07 Volume Flow gal/min1.47E+07 4.556 3.91E+06 1866.915 6342.437 Enthalpy MW −2893.751 −.0001−10844.21 −5456.149 −9602.42 Density lb/cuft 0.025 0.064 0.215 190.163112.823 H₂O 7.00E+06 0 8.41E+06 0 8.41.E+06 HCl 5.67E+06 10.275 10.275 00.006 CO₂ 0 0 0 0 0 O₂ 0 0 0 0 0 N₂ 0 0 0 0 0 MgCl₂ 0 0 0 0 0 MgCl₂*W 00 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 0 0 0 0 0 MgCl₂*6W 0 0 0 0 0Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 0 0 0 0 0 MgO 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 0 0SO₂ 0 0 0 0 0 NO₂ 0 0 0 0 0 NO 0 0 0 0 0 Mg²⁺ 0 0 2494.624 0 1.89E+06Ca²⁺ 0 0 3.11E+06 0 4119.258 Cl⁻ 0 0 5.51E+06 0 5.51E+06 CO₃ ²⁻ 0 0 0 00 HCO₃ ⁻ 0 0 0 0 0 OH⁻ 0 0 0 0 0 CaSiO₃ 0 0 11939.547 11939.547 0 SiO₂ 00 4.67E+06 4.67E+06 9.34E+06 MgSiO₃ 0 0 7.80E+06 7.80E+06 14.153DIOPSIDE 0 0 0 0 0 DOLOMITE 0 0 0 0 0

TABLE 21b Mass and Energy Accounting for Examples 20 and 21 Simulation.Process Stream Names MgCaSiO3 MgCl₂—H MgCl₂—H RECYCLE RECYCLE- SiO₂ PH−0.879 Temperature ° C. 25 100 100 95 95 100 Pressure psia 14.696 14.69614.696 14.696 14.696 14.696 Mass VFrac 0 0 0 0 0 0 Mass SFrac 1 0 1 00.484 1 Mass Flow tons/year 1.68E+07 1.58E+07 1.58E+07 3.27E+07 1.58E+079.34E+06 Volume Flow gal/min 1063.002 4734.61 2804.199 10786.59 2804.1991607.826 Enthalpy MW −7167.458 0 −5533.74 −13087 −5537.26 0 Densitylb/cuft 450.627 94.994 160.371 86.167 160.371 165.327 H₂O 0 8.41E+06 01.68E+07 0 0 HCl 0 0 0 0 0 0 CO₂ 0 0 0 0 0 0 O₂ 0 0 0 0 0 0 N₂ 0 0 0 0 00 MgCl₂ 0 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 0 MgCl₂*4W 00 0 0 0 0 MgCl₂*6W 0 0 1.58E+07 1.58E+07 1.58E+07 0 Mg(OH)Cl 0 0 0 0 0 0Mg(OH)₂ 0 0 0 11678.01 0 0 MgO 0 0 0 0 0 0 MgHCO₃ ⁺ 0 0 0 908.901 0 0SO₂ 0 0 0 0 0 0 NO₂ 0 0 0 0 0 0 NO 0 0 0 0 0 0 Mg²⁺ 0 1.89E+06 0 0 0 0Ca²⁺ 0 4119.258 0 0 0 0 Cl⁻ 0 5.51E+06 0 377.667 0 0 CO₃ ²⁻ 0 0 0 0 0 0HCO₃ ⁻ 0 0 0 0.006 0 0 OH⁻ 0 0 0 0 0 0 CaSiO₃ 0 0 0 0 0 0 SiO₂ 0 0 0 0 09.34E+06 MgSiO₃ 0 0 0 0 0 14.153 DIOPSIDE 1.68E+07 0 0 0 0 0 DOLOMITE 00 0 0 0 0 Process Stream Names SLURRY SOLIDS SOLIDS-1 SOLIDS-2 VENT PH5.271 8.545 Temperature ° C. 95 95 450 95 95 Pressure psia 14.696 14.69614.696 14.696 14.696 Mass VFrac 0 0 0 0 1 Mass SFrac 1 0.177 1 1 0.558Mass Flow tons/year 1.70E+08 1.43E+07 6.27E+06 1.63E+07 1.23E+08 VolumeFlow gal/min 183332.5 2276.772 797.11 5155.892 5.85E+07 Enthalpy MW−19788.2 0 −2603.98 −7331.92 −1510.64 Density lb/cuft 26.409 178.921223.695 89.754 0.06 H₂O 1.68E+07 0 0 7.20E+06 0 HCl 0 0 0 0 0 CO₂6.85E+06 0 0 0 6.85E+06 O₂ 1.37E+07 0 0 0 1.37E+07 N₂ 1.03E+08 0 0 01.03E+08 MgCl₂ 0 0 0 0 0 MgCl₂*W 0 0 0 0 0 MgCl₂*2W 0 0 0 0 0 MgCl₂*4W 00 0 0 0 MgCl₂*6W 1.58E+07 0 0 0 0 Mg(OH)Cl 0 0 0 0 0 Mg(OH)₂ 11678.01 00 9.07E+06 0 MgO 0 0 6.27E+06 0 0 MgHCO₃ ⁺ 908.901 0 0 0 0 SO₂ 0 0 0 0 0NO₂ 0 0 0 0 0 NO 0 0 0 0 0 Mg²⁺ 0 0 0 14.555 0 Ca²⁺ 0 0 0 0 0 Cl⁻377.667 0 0 0 0 CO₃ ²⁻ 0 0 0 0 0 HCO₃ ⁻ 0.006 0 0 0 0 OH⁻ 0 0 0 0 0CaSiO₃ 0 0 0 0 0 SiO₂ 0 0 0 0 0 MgSiO₃ 0 0 0 0 0 DIOPSIDE 0 0 0 0 0DOLOMITE 1.43E+07 1.43E+07

Example 22 Decomposition of Other Salts

The thermal decomposition of other salts has been measured in lab. Asummary of some test results are shown in the table below.

TABLE 22 Decomposition of other salts. Temp. Time Salt ° C. (min.)Results Mg(NO₃)₂ 400 30 63% decomposition. Reaction is Mg(NO₃)₂ → MgO +2NO₂ + ½ O₂ Mg(NO₃)₂ 400 45   64% decomposition. Mg(NO₃)₂ 400 90 100%decomposition Mg(NO₃)₂ 400 135 100% decomposition Ca(NO₃)₂ 400 30 <25%decomposition Reaction is Ca(NO₃)₂ → CaO + 2NO₂ + ½ O₂ Ca(NO₃)₂ 600 50 61% decomposition Ca(NO₃)₂ 600 Overnight 100% decomposition LiCl 450120  ~0% decomposition

Example 22 Two, Three and Four-Chamber Decomposition Models

Table 23 (see below) is a comparison of the four configurationscorresponding to FIGS. 31-34. Depicted are the number and description ofthe chambers, the heat consumed in MW (Megawatts), the percentage ofheat from that particular source and the reduction of required externalheat in kW-H/tonne of CO₂ because of available heat from other reactionsin the process, namely the hydrochloric acid reaction with mineralsilicates and the condensation of hydrochloric acid. In the FIG. 34example, the hot flue gas from the open-cycle natural gas plant alsoqualifies.

Example 23 Output Mineral Compared with Input Minerals—Coal

In this case study involving flue gas from a coal-based power plant,Table 24 illustrates that the volume of mineral outputs (limestone andsand) are 83% of the volume of input minerals (coal and inosilicate).The results summarized in Table 24 are based on a 600 MWe coal plant;total 4.66 E6 tonne CO₂, includes CO₂ for process-required heat.

Example 24 Output Mineral Compared with Input Minerals—Natural Gas

In this case study summarized in Table 25 (below) involving flue gasfrom a natural gas-based power plant, the “rail-back volume” of mineralsis 92% of the “rail-in volume” of minerals. The results summarized inTable 25 are (based on a 600 MWe CC natural gas plant; total 2.41 E6tonne CO₂, which includes CO₂ for process-required heat.

TABLE 23 Two, Three and Four-Chamber Decomposition Results ChamberDescription Pre-heat Pre Heat Pre-Heat Mineral Dissolution Reactor No.of Cold from Silicate HCl Heat Example Chambers Flue Gas Steam ReactionRecovery Decomposition FIG. 31 Cold Flue Gas Pre Heat 3 MW of Heat 83.9Not used  286  563  86.8 Percentage of Total Heat 8.2% Not used    28.0%   55.2%   8.5% Reduction kW-Hr/tonne −506.7 Not used −1727.4 −3400.5Not a reduction FIG. 32 Cold Flue Gas and Steam Pre -Heat 4 MW of Heat83.9 8.7  286  563  82.2 Percentage of Total Heat 8.2% 0.8%    27.9%   55.0%   8.0% Reduction kW-Hr/tonne −506.7 −52.5 −1727.4 −3400.5 Not areduction FIG. 33 Nat Gas Only 2 MW of Heat Not used Not used  279  586129.3 Percentage of Total Heat Not used Not used   28%   59%  13%Reduction kW-Hr/tonne Not used Not used −1685.1 −3539.4 Not a reductionFIG. 34 Hot Flue Gas Only 2 MW of Heat Not used Not used  243  512 112.9Percentage of Total Heat Not used Not used   28%   59%  13% ReductionkW-Hr/tonne Not used Not used −1467.7 −3092.4 −681.9 

TABLE 24 Coal Scenario - Volume of Mineral Outputs Compared with Volumeof Mineral Inputs Metric Units English Units Bulk Mass Volume MassVolume Density (10⁶ (10⁶ (10⁶ (10⁶ Parameter (Tonne/m³) Tonne/yr) m³/yr)Ton/yr) ft³/yr) Coal 0.8 1.57 1.97 1.73 69.5 CaSiO₃ 0.71 12.30 17.3213.56 611.8 Coal + CaSiO₃ 681.25 CaCO₃ 0.9 10.60 11.78 11.68 415.9 SiO₂1.5 6.35 4.23 7.00 149.5 CaCO₃ + SiO₂ n/a 16.95 16.01 18.68 565.4 RATIOOF MINERAL VOLUME OUT/MINERAL 83.00% VOLUME IN =

TABLE 25 Natural Gas Scenario - Volume of Mineral Outputs Compared withVolume of Mineral Inputs Metric Units English Units Bulk Mass VolumeMass Volume Density (10⁶ (10⁶ (10⁶ (10⁶ Parameter (Tonne/m³) Tonne/yr)m³/yr) Ton/yr) ft³/yr) Coal 0.8 1.57 1.97 1.73 69.5 CaSiO₃ 0.71 12.3017.32 13.56 611.8 Coal + CaSiO₃ 681.25 CaCO₃ 0.9 10.60 11.78 11.68 415.9SiO₂ 1.5 6.35 4.23 7.00 149.5 CaCO₃ + SiO₂ n/a 16.95 16.01 18.68 565.4RATIO OF MINERAL VOLUME OUT/MINERAL 83.00% VOLUME IN =

All of the methods disclosed and claimed herein can be made and executedwithout undue experimentation in light of the present disclosure. Whilethe compositions and methods of this invention have been described interms of particular embodiments, it will be apparent to those of skillin the art that variations may be applied to the methods and in thesteps or in the sequence of steps of the method described herein withoutdeparting from the concept, spirit and scope of the invention. All suchsimilar substitutes and modifications apparent to those skilled in theart are deemed to be within the spirit, scope and concept of theinvention as defined by the appended claims.

REFERENCES

The following references, to the extent that they provide exemplaryprocedural or other details supplementary to those set forth herein, arespecifically incorporated herein by reference.

-   U.S. Prov. Appln. 60/612,355-   U.S. Prov. Appln. 60/642,698-   U.S. Prov. Appln. 60/718,906-   U.S. Prov. Appln. 60/973,948-   U.S. Prov. Appln. 61/032,802-   U.S. Prov. Appln. 61/033,298-   U.S. Prov. Appln. 61/288,242-   U.S. Prov. Appln. 61/362,607-   U.S. patent application Ser. No. 11/233,509-   U.S. patent application Ser. No. 12/235,482-   U.S. Patent Pubn. 2006/0185985-   U.S. Patent Pubn. 2009/0127127-   U.S. Pat. No. 7,727,374-   PCT Appln. PCT/US08/77122-   Goldberg et al., Proceedings of First National Conference on Carbon    Sequestration, 14-17 May 2001, Washington, D.C., section 6c, United    States Department of Energy, National Energy Technology Laboratory.    available at:    http://www.netl.doe.gov/publications/proceedings/01/carbon_seq/6cl.pdf.-   Proceedings of First National Conference on Carbon Sequestration,    14-17 May 2001, Washington, D.C. United States Department of Energy,    National Energy Technology Laboratory. CD-ROM USDOE/NETL-2001/1144;    also available at    http://www.netl.doe.gov/publications/proceedings/01/carbon_seq/carbon_seq01.html.

1. A method of sequestering carbon dioxide produced by a source,comprising: (a) reacting a first cation-based halide, sulfate or nitratesalt or hydrate thereof with water in a first admixture under conditionssuitable to form a first product mixture comprising a first step (a)product comprising a first cation-based hydroxide salt, a firstcation-based oxide salt and/or a first cation-based hydroxychloride saltand a second step (a) product comprising HCl, H₂SO₄ or HNO₃; (b)admixing some or all of the first step (a) product with a secondcation-based halide, sulfate or nitrate salt or hydrate thereof andcarbon dioxide produced by the source in a second admixture underconditions suitable to form a second product mixture comprising a firststep (b) product comprising a first-cation-based halide, sulfate and/ornitrate salt or hydrate thereof, a second step (b) product comprising asecond cation-based carbonate salt, and a third step (b) productcomprising water; and (c) separating some or all of the secondcation-based carbonate salt from the second product mixture, whereby thecarbon dioxide is sequestered into a mineral product form.
 2. The methodof claim 1, wherein the first cation-based halide, sulfate or nitratesalt or hydrate thereof of step (a) is a first cation-based chloridesalt or hydrate thereof, and the second step (a) product is HCl.
 3. Themethod according to claim 1, wherein the first cation-based halide,sulfate, or nitrate salt or hydrate thereof of step (b) is a firstcation-based chloride salt or hydrate thereof.
 4. The method of claim 2,wherein the first cation-based chloride salt or hydrate thereof of step(a) is MgCl₂.
 5. The method of claim 4, wherein the first cation-basedchloride salt or hydrate thereof of step (a) is a hydrated form ofMgCl₂.
 6. The method of claim 5, wherein the first cation-based chloridesalt or hydrate thereof of step (a) is MgCl₂.6H₂O.
 7. The methodaccording to claim 1, wherein the first cation-based hydroxide salt ofstep (a) is Mg(OH)₂.
 8. The method according to claim 2, wherein thefirst cation-based hydroxychloride salt of step (a) is Mg(OH)Cl.
 9. Themethod of claim 8, wherein the first step (a) product comprisespredominantly Mg(OH)Cl.
 10. The method of claim 8, wherein the firststep (a) product comprises greater than 90% by weight Mg(OH)Cl.
 11. Themethod of claim 8, wherein the first step (a) product is Mg(OH)Cl. 12.The method according to claim 1, wherein the first cation-based oxidesalt of step (a) is MgO.
 13. The method according to claim 1, whereinthe second cation-based halide, sulfate or nitrate salt or hydratethereof of step (b) is a second cation-based chloride salt or hydratethereof.
 14. The method of claim 13, wherein the second cation-basedchloride salt or hydrate thereof is CaCl₂.
 15. The method according toclaim 3, wherein the first cation-based chloride salt of step (b) isMgCl₂.
 16. The method of claim 15, wherein the first cation-basedchloride salt of step (b) is a hydrated form of MgCl₂.
 17. The method ofclaim 15, wherein the first cation-based chloride salt of step (b) isMgCl₂.6H₂O.
 18. The method according to claim 1, where some or all ofthe water in step (a) is present in the form of steam or supercriticalwater.
 19. The method according to claim 1, where some or all of thewater of step (a) is obtained from the water of step (b).
 20. The methodaccording to claim 1, wherein step (b) further comprises admixing sodiumhydroxide salt in the second admixture.
 21. A method of claim 1, furthercomprising: (d) admixing a Group 2 silicate mineral with HCl underconditions suitable to form a third product mixture comprising a Group 2chloride salt, water, and silicon dioxide.
 22. The method of claim 21,where some or all of the HCl in step (d) is obtained from step (a). 23.The method of claim 21, wherein the HCl of step (d) further comprisesagitating the Group 2 silicate mineral with HCl.
 24. The methodaccording to claim 21, wherein some or all of the heat generated in step(d) is recovered.
 25. The method according to claim 21, where some orall of the second cation-based chloride salt of step (b) is the Group 2chloride salt of step (d).
 26. The method according to claim 21, furthercomprising a separation step, wherein the silicon dioxide is removedfrom the Group 2 chloride salt formed in step (d).
 27. The methodaccording to claim 21, where some or all of the water of step (a) isobtained from the water of step (d).
 28. The method according to claim21, wherein the Group 2 silicate mineral of step (d) comprises a Group 2inosilicate.
 29. The method according to claim 21, wherein the Group 2silicate mineral of step (d) comprises CaSiO₃.
 30. The method accordingto claim 21, wherein the Group 2 silicate mineral of step (d) comprisesMgSiO₃.
 31. The method according to claim 21, wherein the Group 2silicate mineral of step (d) comprises olivine (Mg₂[SiO₄]).
 32. Themethod according to claim 21, wherein the Group 2 silicate mineral ofstep (d) comprises serpentine (Mg₆[OH]₈[Si₄O₁₀]).
 33. The methodaccording to claim 21, wherein the Group 2 silicate mineral of step (d)comprises sepiolite (Mg₄[(OH)₂Si₆O₁₅].6H₂O), enstatite (Mg₂[Si₂O₆]),diopside (CaMg[Si₂O₆]), and/or tremolite Ca₂Mg₅{[OH]Si₄O₁₁}₂.
 34. Themethod according to claim 21, wherein the Group 2 silicate furthercomprises iron and or manganese silicates.
 35. The method of claim 34,wherein the iron silicate is fayalite (Fe₂[SiO₄]).
 36. The methodaccording to claim 3, wherein some or all of the first cation-basedchloride salt formed in step (b) is the first cation-based chloride saltused in step (a).
 37. The method according to claim 1, wherein thecarbon dioxide is in the form of flue gas, wherein the flue gas furthercomprises N₂ and H₂O.
 38. The method according to claim 1, whereinsuitable reacting conditions of step (a) comprise a temperature fromabout 200° C. to about 500° C.
 39. The method of claim 38, wherein thetemperature is from about 230° C. to about 260° C.
 40. The method ofclaim 38, wherein the temperature is about 250° C.
 41. The method ofclaim 38, wherein the temperature is from about 200° C. to about 250° C.42. The method of claim 38, wherein the temperature is about 240° C. 43.The method according to claim 1, wherein suitable reacting conditions ofstep (a) comprise a temperature from about 50° C. to about 200° C. 44.The method of claim 43, wherein the temperature is from about 90° C. toabout 260° C.
 45. The method of claim 44, wherein the temperature isfrom about 90° C. to about 230° C.
 46. The method of claim 45, whereinthe temperature is about 130° C.
 47. The method according to claim 1,wherein suitable reacting conditions of step (a) comprise a temperaturefrom about 400° C. to about 550° C.
 48. The method of claim 47, whereinthe temperature is from about 450° C. to about 500° C.
 49. The methodaccording to claim 1, wherein suitable reacting conditions of step (b)comprise a temperature from about 20° C. to about 100° C.
 50. The methodof claim 49, wherein the temperature is from about 25° C. to about 95°C.
 51. The method according to claim 21, wherein suitable reactingconditions of step (d) comprise a temperature from about 50° C. to about200° C.
 52. The method of claim 51, wherein the temperature is fromabout 90° C. to about 150° C.
 53. A method of sequestering carbondioxide produced by a source, comprising: (a) admixing a magnesiumchloride salt and water in a first admixture under conditions suitableto form (i) magnesium hydroxide, magnesium oxide and/or Mg(OH)Cl and(ii) hydrogen chloride; (b) admixing (i) magnesium hydroxide, magnesiumoxide and/or Mg(OH)Cl, (ii) CaCl₂ and (iii) carbon dioxide produced bythe source in a second admixture under conditions suitable to form (iv)calcium carbonate, (v) a magnesium chloride salt, and (vi) water; and(c) separating the calcium carbonate from the second admixture, wherebythe carbon dioxide is sequestered into a mineral product form.
 54. Themethod of claim 53, wherein some or all of the hydrogen chloride of step(a) is admixed with water to form hydrochloric acid.
 55. The method ofclaim 53, where some or all of the magnesium hydroxide, magnesium oxideand/or Mg(OH)Cl of step (b)(i) is obtained from step (a)(i).
 56. Themethod of claim 53, where some of all the water in step (a) is presentin the form of a hydrate of the magnesium chloride salt.
 57. The methodof claim 53, wherein step (a) occurs in one, two or three reactors. 58.The method of claim 53, wherein step (a) occurs in one reactor.
 59. Themethod of claim 53, wherein the magnesium hydroxide, magnesium oxideand/or Mg(OH)Cl of step (a)(i) is greater than 90% by weight Mg(OH)Cl.60. The method of claim 53, wherein the magnesium chloride salt isgreater than 90% by weight MgCl₂.6(H₂O).
 61. The method of claim 53,further comprising: (d) admixing a Group 2 silicate mineral withhydrogen chloride under conditions suitable to form a Group 2 chloridesalt, water, and silicon dioxide.
 62. The method of claim 61, where someor all of the hydrogen chloride in step (d) is obtained from step (a).63. The method of claim 61, wherein step (d) further comprises agitatingthe Group 2 silicate mineral with the hydrochloric acid.
 64. The methodof claim 61, where some or all of the magnesium chloride salt in step(a) is obtained from step (d).
 65. The method of claim 61, furthercomprising a separation step, wherein the silicon dioxide is removedfrom the Group 2 chloride salt formed in step (d).
 66. The method ofclaim 61, where some or all of the water of step (a) is obtained fromthe water of step (d).
 67. The method of claim 61, wherein the Group 2silicate mineral of step (d) comprises a Group 2 inosilicate.
 68. Themethod of claim 61 wherein the Group 2 silicate mineral of step (d)comprises CaSiO₃.
 69. The method of claim 61, wherein the Group 2silicate mineral of step (d) comprises MgSiO₃.
 70. The method of claim61, wherein the Group 2 silicate mineral of step (d) comprises olivine.71. The method of claim 61, wherein the Group 2 silicate mineral of step(d) comprises serpentine.
 72. The method of claim 61, wherein the Group2 silicate mineral of step (d) comprises sepiolite, enstatite, diopside,and/or tremolite.
 73. The method of claim 61 wherein the Group 2silicate further comprises mineralized iron and or manganese.
 74. Themethod according to claim 53, wherein step (b) further comprisesadmixing CaCl₂ and water to the second admixture.